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mariadb/sql/sql_base.h

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Fix for bug#14188793 - "DEADLOCK CAUSED BY ALTER TABLE DOEN'T CLEAR STATUS OF ROLLBACKED TRANSACTION" and bug #17054007 - "TRANSACTION IS NOT FULLY ROLLED BACK IN CASE OF INNODB DEADLOCK". The problem in the first bug report was that although deadlock involving metadata locks was reported using the same error code and message as InnoDB deadlock it didn't rollback transaction like the latter. This caused confusion to users as in some cases after ER_LOCK_DEADLOCK transaction could have been restarted immediately and in some cases rollback was required. The problem in the second bug report was that although InnoDB deadlock caused transaction rollback in all storage engines it didn't cause release of metadata locks. So concurrent DDL on the tables used in transaction was blocked until implicit or explicit COMMIT or ROLLBACK was issued in the connection which got InnoDB deadlock. The former issue has stemmed from the fact that when support for detection and reporting metadata locks deadlocks was added we erroneously assumed that InnoDB doesn't rollback transaction on deadlock but only last statement (while this is what happens on InnoDB lock timeout actually) and so didn't implement rollback of transactions on MDL deadlocks. The latter issue was caused by the fact that rollback of transaction due to deadlock is carried out by setting THD::transaction_rollback_request flag at the point where deadlock is detected and performing rollback inside of trans_rollback_stmt() call when this flag is set. And trans_rollback_stmt() is not aware of MDL locks, so no MDL locks are released. This patch solves these two problems in the following way: - In case when MDL deadlock is detect transaction rollback is requested by setting THD::transaction_rollback_request flag. - Code performing rollback of transaction if THD::transaction_rollback_request is moved out from trans_rollback_stmt(). Now we handle rollback request on the same level as we call trans_rollback_stmt() and release statement/ transaction MDL locks.
2013-08-20 11:12:34 +02:00
/* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
Merge branch 'mysql/5.5' into 5.5
2018-04-19 22:27:02 +02:00
Copyright (c) 2011, 2018, MariaDB
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Update FSF Address * Update wrong zip-code
2019-05-11 20:29:06 +02:00
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
#ifndef SQL_BASE_INCLUDED
#define SQL_BASE_INCLUDED
cleanup: renames enum_mark_columns -> enum_column_usage mark_used_columns -> column_usage further commits will replace MARK_COLUMN_NONE with COLUMN_READ and COLUMN_WRITE that convey the intention without causing columns to be marked
2018-02-09 19:43:42 +01:00
#include "sql_class.h" /* enum_column_usage */
MDEV-6112 multiple triggers per table This is similar to MysQL Worklog 3253, but with a different implementation. The disk format and SQL syntax is identical with MySQL 5.7. Fetures supported: - "Any" ammount of any trigger - Supports FOLLOWS and PRECEDES to be able to put triggers in a certain execution order. Implementation details: - Class Trigger added to hold information about a trigger. Before this trigger information was stored in a set of lists in Table_triggers_list and in Table_triggers_list::bodies - Each Trigger has a next field that poinst to the next Trigger with the same action and time. - When accessing a trigger, we now always access all linked triggers - The list are now only used to load and save trigger files. - MySQL trigger test case (trigger_wl3253) added and we execute these identically. - Even more gracefully handling of wrong trigger files than before. This is useful if a trigger file uses functions or syntax not provided by the server. - Each trigger now has a "Created" field that shows when the trigger was created, with 2 decimals. Other comments: - Many of the changes in test files was done because of the new "Created" field in the trigger file. This shows up in SHOW ... TRIGGER and when using information_schema.trigger. - Don't check if all memory is released if on uses --gdb; This is needed to be able to get a list from safemalloc of not freed memory while debugging. - Added option to trim_whitespace() to know how many prefix characters was skipped. - Changed a few ulonglong sql_mode to sql_mode_t, to find some wrong usage of sql_mode.
2016-10-02 14:35:08 +02:00
#include "sql_trigger.h" /* trg_event_type */
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
#include "mysqld.h" /* key_map */
MDEV-4702 - Reduce usage of LOCK_open Following variables do not require LOCK_open protection anymore: - table_def_cache (renamed to tdc_hash) is protected by rw-lock LOCK_tdc_hash; - table_def_shutdown_in_progress doesn't need LOCK_open protection; - last_table_id use atomics; - TABLE_SHARE::ref_count (renamed to TABLE_SHARE::tdc.ref_count) is protected by TABLE_SHARE::tdc.LOCK_table_share; - TABLE_SHARE::next, ::prev (renamed to tdc.next and tdc.prev), oldest_unused_share, end_of_unused_share are protected by LOCK_unused_shares; - TABLE_SHARE::m_flush_tickets (renamed to tdc.m_flush_tickets) is protected by TABLE_SHARE::tdc.LOCK_table_share; - refresh_version (renamed to tdc_version) use atomics.
2013-08-14 10:48:50 +02:00
#include "table_cache.h"
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
class Item_ident;
A post-fix patch for WL#4877/WL#5030: Fix tons of warnings about mismatch struct and class usage.
2010-04-12 15:17:37 +02:00
struct Name_resolution_context;
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
class Open_table_context;
class Open_tables_state;
class Prelocking_strategy;
A post-fix patch for WL#4877/WL#5030: Fix tons of warnings about mismatch struct and class usage.
2010-04-12 15:17:37 +02:00
struct TABLE_LIST;
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
class THD;
A post-fix patch for WL#4877/WL#5030: Fix tons of warnings about mismatch struct and class usage.
2010-04-12 15:17:37 +02:00
struct handlerton;
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
struct TABLE;
typedef class st_select_lex SELECT_LEX;
typedef struct st_lock_param_type ALTER_PARTITION_PARAM_TYPE;
/*
This enumeration type is used only by the function find_item_in_list
to return the info on how an item has been resolved against a list
of possibly aliased items.
The item can be resolved:
- against an alias name of the list's element (RESOLVED_AGAINST_ALIAS)
- against non-aliased field name of the list (RESOLVED_WITH_NO_ALIAS)
- against an aliased field name of the list (RESOLVED_BEHIND_ALIAS)
- ignoring the alias name in cases when SQL requires to ignore aliases
(e.g. when the resolved field reference contains a table name or
when the resolved item is an expression) (RESOLVED_IGNORING_ALIAS)
*/
enum enum_resolution_type {
NOT_RESOLVED=0,
RESOLVED_IGNORING_ALIAS,
RESOLVED_BEHIND_ALIAS,
RESOLVED_WITH_NO_ALIAS,
RESOLVED_AGAINST_ALIAS
};
Added new MDL_BACKUP locks for all backup stages Part of MDEV-5336 Implement LOCK FOR BACKUP - Added new locks to MDL_BACKUP for all stages of backup locks and a new MDL lock needed for backup stages. - Renamed MDL_BACKUP_STMT to MDL_BACKUP_DDL - flush_tables() takes a new parameter that decides what should be flushed. - InnoDB, Aria (transactional tables with checksums), Blackhole, Federated and Federatedx tables are marked to be safe for online backup. We are using MDL_BACKUP_TRANS_DML instead of MDL_BACKUP_DML locks for these which allows any DML's to proceed for these tables during the whole backup process until BACKUP STAGE COMMIT which will block the final commit.
2018-11-06 16:05:24 +01:00
/* Argument to flush_tables() of what to flush */
enum flush_tables_type {
FLUSH_ALL,
FLUSH_NON_TRANS_TABLES,
FLUSH_SYS_TABLES
};
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
enum find_item_error_report_type {REPORT_ALL_ERRORS, REPORT_EXCEPT_NOT_FOUND,
IGNORE_ERRORS, REPORT_EXCEPT_NON_UNIQUE,
IGNORE_EXCEPT_NON_UNIQUE};
MDEV-11129 CREATE OR REPLACE TABLE t1 AS SELECT spfunc() crashes if spfunc() references t1 Fixed by extending unique_table() with a flag to not allow usage of the replaced table. I also cleaned up find_dup_table() to not use goto next. I also added more comments to the code in find_dup_table()
2018-05-16 20:51:46 +02:00
/* Flag bits for unique_table() */
#define CHECK_DUP_ALLOW_DIFFERENT_ALIAS 1
#define CHECK_DUP_FOR_CREATE 2
MDEV-16192 Table 't' is specified twice, both as a target for 'CREATE' and... as a separate source for data Actually MDEV-15867 and MDEV-16192 are same, Slave adds "or replace" to create table stmt. So create table t1 is create or replace on slave. So this bug is not because of replication, We can get this bug on general server if we manually add or replace to create query. Problem:- So if we try to create table t1 (same name as of temp table t1 ) via CREATE or replace TABLE t AS SELECT * FROM t; Since in this query we are creating table from select * from t1 , we call unique_table function to see whether if source and destination table are same. But there is one issue unique_table does not account if source table is tmp table in this case source and destination table can be same. Solution:- We will change find_dup_table to not to look for temp table if CHECK_DUP_SKIP_TEMP_TABLE flag is on.
2018-06-26 08:03:58 +02:00
#define CHECK_DUP_SKIP_TEMP_TABLE 4
MDEV-11129 CREATE OR REPLACE TABLE t1 AS SELECT spfunc() crashes if spfunc() references t1 Fixed by extending unique_table() with a flag to not allow usage of the replaced table. I also cleaned up find_dup_table() to not use goto next. I also added more comments to the code in find_dup_table()
2018-05-16 20:51:46 +02:00
Applied all changes from Igor and Sanja
2013-06-15 17:32:08 +02:00
uint get_table_def_key(const TABLE_LIST *table_list, const char **key);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type update,
uint lock_flags);
Extract reload_acl_and_cache() and flush_tables_with_read_lock() into an own implementation file.
2010-08-13 11:51:48 +02:00
/* mysql_lock_tables() and open_table() flags bits */
#define MYSQL_OPEN_IGNORE_GLOBAL_READ_LOCK 0x0001
#define MYSQL_OPEN_IGNORE_FLUSH 0x0002
merge of 2876.430.11 & 2876.430.1 CF_PREOPEN_TMP_TABLES & CF_HA_CLOSE & Patch for Bug#11746602 (27480: Extend CREATE TEMPORARY TABLES privilege to allow temp table operations).
2013-06-27 16:42:18 +02:00
/* MYSQL_OPEN_TEMPORARY_ONLY (0x0004) is not used anymore. */
Extract reload_acl_and_cache() and flush_tables_with_read_lock() into an own implementation file.
2010-08-13 11:51:48 +02:00
#define MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY 0x0008
#define MYSQL_LOCK_LOG_TABLE 0x0010
/**
Do not try to acquire a metadata lock on the table: we
already have one.
*/
#define MYSQL_OPEN_HAS_MDL_LOCK 0x0020
/**
If in locked tables mode, ignore the locked tables and get
a new instance of the table.
*/
#define MYSQL_OPEN_GET_NEW_TABLE 0x0040
merge of 2876.430.11 & 2876.430.1 CF_PREOPEN_TMP_TABLES & CF_HA_CLOSE & Patch for Bug#11746602 (27480: Extend CREATE TEMPORARY TABLES privilege to allow temp table operations).
2013-06-27 16:42:18 +02:00
/* 0x0080 used to be MYSQL_OPEN_SKIP_TEMPORARY */
Extract reload_acl_and_cache() and flush_tables_with_read_lock() into an own implementation file.
2010-08-13 11:51:48 +02:00
/** Fail instead of waiting when conficting metadata lock is discovered. */
#define MYSQL_OPEN_FAIL_ON_MDL_CONFLICT 0x0100
/** Open tables using MDL_SHARED lock instead of one specified in parser. */
#define MYSQL_OPEN_FORCE_SHARED_MDL 0x0200
/**
Open tables using MDL_SHARED_HIGH_PRIO lock instead of one specified
in parser.
*/
#define MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL 0x0400
/**
When opening or locking the table, use the maximum timeout
(LONG_TIMEOUT = 1 year) rather than the user-supplied timeout value.
*/
#define MYSQL_LOCK_IGNORE_TIMEOUT 0x0800
Fix for bug #55273 "FLUSH TABLE tm WITH READ LOCK for Merge table causes assert failure". Attempting to use FLUSH TABLE table_list WITH READ LOCK statement for a MERGE table led to an assertion failure if one of its children was not present in the list of tables to be flushed. The problem was not visible in non-debug builds. The assertion failure was caused by the fact that in such situations FLUSH TABLES table_list WITH READ LOCK implementation tried to use (e.g. lock) such child tables without acquiring metadata lock on them. This happened because when opening tables we assumed metadata locks on all tables were already acquired earlier during statement execution and a such assumption was false for MERGE children. This patch fixes the problem by ensuring at open_tables() time that we try to acquire metadata locks on all tables to be opened. For normal tables such requests are satisfied instantly since locks are already acquired for them. For MERGE children metadata locks are acquired in normal fashion. Note that FLUSH TABLES merge_table WITH READ LOCK will lock for read both the MERGE table and its children but will flush only the MERGE table. To flush children one has to mention them in table list explicitly. This is expected behavior and it is consistent with usage patterns for this statement (e.g. in mysqlhotcopy script). mysql-test/r/flush.result: Added test case for bug #55273 "FLUSH TABLE tm WITH READ LOCK for Merge table causes assert failure". mysql-test/t/flush.test: Added test case for bug #55273 "FLUSH TABLE tm WITH READ LOCK for Merge table causes assert failure". sql/sql_base.cc: Changed lock_table_names() to support newly introduced MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK flag. sql/sql_base.h: Introduced MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK flag for open_tables() and lock_table_names() which allows to skip acquiring of global and schema-scope locks when SNW, SNRW or X metadata locks are acquired. sql/sql_reload.cc: Changed "FLUSH TABLES table_list WITH READ LOCK" code not to cause assert about missing metadata locks when MERGE table is flushed without one of its underlying tables. To achieve this we no longer call open_and_lock_tables() with MYSQL_OPEN_HAS_MDL_LOCK flag so this function automatically acquires metadata locks on MERGE children if such lock has not been already acquired at earlier stage. Instead we call this function with MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK flag to suppress acquiring of global IX lock in order to keep FLUSH TABLES table_list WITH READ LOCK compatible with FLUSH TABLE WITH READ LOCK. Also changed implementation to use lock_table_names() function for pre-acquiring of metadata locks instead of custom code. To implement this change moved setting of open_type member for table list elements to parser. sql/sql_yacc.yy: Now we set acceptable type of table for FLUSH TABLES table_list WITH READ LOCK at parsing time instead of execution time.
2010-09-09 16:29:14 +02:00
/**
When acquiring "strong" (SNW, SNRW, X) metadata locks on tables to
be open do not acquire global and schema-scope IX locks.
*/
#define MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK 0x1000
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
#define MYSQL_LOCK_NOT_TEMPORARY 0x2000
MDEV 13679 Enabled sequences to be used in DEFAULT Other changes done to get this to work: - Added 'internal_tables' to TABLE object to list which sequence tables is needed to use the table. - Mark any expression using DEFAULT() with LEX->default_used. This is needed when deciding if we should open internal sequence tables when a table is opened (we don't need to open sequence tables if the main table is only used with SELECT). - Create_and_open_temporary_table() can now also open all internal sequence tables. - Added option MYSQL_LOCK_USE_MALLOC to mysql_lock_tables() to force memory allocation to be used with malloc instead of memroot. - Added flag to MYSQL_LOCK to remember if allocation was done with malloc or memroot (makes code simpler and safer). - init_one_table_for_prelocking() now takes argument for what lock to use instead of it's a routine or something else. - Renamed prelocking placeholders to make them more understandable as they are now used in more code. - Changed test in check_lock_and_start_stmt() if found table has correct locks. The old test didn't work for tables that has lock TL_WRITE_ALLOW_WRITE, which is what sequence tables are using. - Added VCOL_NOT_VIRTUAL option to ensure that sequence functions can't be used with virtual columns - More sequence tests
2017-12-22 13:56:09 +01:00
#define MYSQL_LOCK_USE_MALLOC 0x4000
Applied all changes from Igor and Sanja
2013-06-15 17:32:08 +02:00
/**
Only check THD::killed if waits happen (e.g. wait on MDL, wait on
table flush, wait on thr_lock.c locks) while opening and locking table.
*/
10.0-monty merge includes: * remove some remnants of "Bug#14521864: MYSQL 5.1 TO 5.5 BUGS PARTITIONING" * introduce LOCK_share, now LOCK_ha_data is strictly for engines * rea_create_table() always creates .par file (even in "frm-only" mode) * fix a 5.6 bug, temp file leak on dummy ALTER TABLE
2013-07-21 16:39:19 +02:00
#define MYSQL_OPEN_IGNORE_KILLED 0x8000
MDEV-9621 INSERT DELAYED fails on insert for tables with many columns This fix also fixes a connection hang when trying to do INSERT DELAYED to a crashed table. Added crash_mysqld.inc to allow easy crash+restart of mysqld
2016-04-07 18:26:25 +02:00
/**
Don't try to auto-repair table
*/
#define MYSQL_OPEN_IGNORE_REPAIR 0x10000
Extract reload_acl_and_cache() and flush_tables_with_read_lock() into an own implementation file.
2010-08-13 11:51:48 +02:00
/** Please refer to the internals manual. */
#define MYSQL_OPEN_REOPEN (MYSQL_OPEN_IGNORE_FLUSH |\
MYSQL_OPEN_IGNORE_GLOBAL_READ_LOCK |\
MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY |\
MYSQL_LOCK_IGNORE_TIMEOUT |\
MYSQL_OPEN_GET_NEW_TABLE |\
MYSQL_OPEN_HAS_MDL_LOCK)
MDEV-15890 Strange error message if you try to FLUSH TABLES <view> after LOCK TABLES <view>. Check if the argument of the FLUSH TABLE is a VIEW and handle it accordingly.
2018-09-02 07:24:33 +02:00
bool is_locked_view(THD *thd, TABLE_LIST *t);
MDEV-7671: Cache VIEW definitions in the TDC (changes of backported patch are very small: strlen removed, error processing fixed, view open statistics added)
2015-03-10 10:24:20 +01:00
bool open_table(THD *thd, TABLE_LIST *table_list, Open_table_context *ot_ctx);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
bool get_key_map_from_key_list(key_map *map, TABLE *table,
List<String> *index_list);
TABLE *find_locked_table(TABLE *list, const char *db, const char *table_name);
TABLE *find_write_locked_table(TABLE *list, const char *db,
const char *table_name);
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
thr_lock_type read_lock_type_for_table(THD *thd,
Query_tables_list *prelocking_ctx,
MDEV-6050 MySQL Bug#13036505 62540: TABLE LOCKS WITHIN STORED FUNCTIONS ARE BACK IN 5.5 WITH MIXED AND ROW BI cherry-pick revno 4053 committer: Gopal Shankar <gopal.shankar@oracle.com> branch nick: sf_mysql-5.6 timestamp: Fri 2012-07-20 12:25:34 +0530 message: Bug#13036505 62540: TABLE LOCKS WITHIN STORED FUNCTIONS ARE BACK IN 5.5 WITH MIXED AND ROW BI.
2014-07-31 12:03:20 +02:00
TABLE_LIST *table_list,
bool routine_modifies_data);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
my_bool mysql_rm_tmp_tables(void);
void close_tables_for_reopen(THD *thd, TABLE_LIST **tables,
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
const MDL_savepoint &start_of_statement_svp);
Merge branch '10.2' into 10.3
2018-09-26 20:49:51 +02:00
bool table_already_fk_prelocked(TABLE_LIST *tl, LEX_CSTRING *db,
LEX_CSTRING *table, thr_lock_type lock_type);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
TABLE_LIST *find_table_in_list(TABLE_LIST *table,
TABLE_LIST *TABLE_LIST::*link,
Changed database, tablename and alias to be LEX_CSTRING This was done in, among other things: - thd->db and thd->db_length - TABLE_LIST tablename, db, alias and schema_name - Audit plugin database name - lex->db - All db and table names in Alter_table_ctx - st_select_lex db Other things: - Changed a lot of functions to take const LEX_CSTRING* as argument for db, table_name and alias. See init_one_table() as an example. - Changed some function arguments from LEX_CSTRING to const LEX_CSTRING - Changed some lists from LEX_STRING to LEX_CSTRING - threads_mysql.result changed because process list_db wasn't always correctly updated - New append_identifier() function that takes LEX_CSTRING* as arguments - Added new element tmp_buff to Alter_table_ctx to separate temp name handling from temporary space - Ensure we store the length after my_casedn_str() of table/db names - Removed not used version of rename_table_in_stat_tables() - Changed Natural_join_column::table_name and db_name() to never return NULL (used for print) - thd->get_db() now returns db as a printable string (thd->db.str or "")
2018-01-07 17:03:44 +01:00
const LEX_CSTRING *db_name,
const LEX_CSTRING *table_name);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
void close_thread_tables(THD *thd);
MDEV-8605 MariaDB not use DEFAULT value even when inserted NULL for NOT NULLABLE column NOT NULL constraint must be checked *after* the BEFORE triggers. That is for INSERT and UPDATE statements even NOT NULL fields must be able to store a NULL temporarily at least while BEFORE INSERT/UPDATE triggers are running.
2015-11-14 22:51:54 +01:00
void switch_to_nullable_trigger_fields(List<Item> &items, TABLE *);
various cleanups * remove a confusing method name - Field::set_default_expression() * remove handler::register_columns_for_write() * rename stuff * add asserts * remove unlikely unlikely * remove redundant if() conditions * fix mark_unsupported_function() to report the most important violation * don't scan vfield list for default values (vfields don't have defaults) * move handling for DROP CONSTRAINT IF EXIST where it belongs * don't protect engines from Alter_inplace_info::ALTER_ADD_CONSTRAINT * comments
2016-06-29 21:27:34 +02:00
void switch_defaults_to_nullable_trigger_fields(TABLE *table);
MDEV-452 Add full support for auto-initialized/updated timestamp and datetime Generalized support for auto-updated and/or auto-initialized timestamp and datetime columns. This patch is a reimplementation of MySQL's "WL#5874: CURRENT_TIMESTAMP as DEFAULT for DATETIME columns". In order to ease future merges, this implementation reused few function and variable names from MySQL's patch, however the implementation is quite different. TODO: The only unresolved problem in this patch is the semantics of LOAD DATA for TIMESTAMP and DATETIME columns in the cases when there are missing or NULL columns. I couldn't fully comprehend the logic behind MySQL's behavior and its relationship with their own documentation, so I left the results to be more consistent with all other LOAD cases. The problematic test cases can be seen by running the test file function_defaults, and observing the test case differences. Those were left on purpose for discussion.
2012-10-17 14:43:56 +02:00
bool fill_record_n_invoke_before_triggers(THD *thd, TABLE *table,
List<Item> &fields,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
List<Item> &values,
bool ignore_errors,
enum trg_event_type event);
MDEV-452 Add full support for auto-initialized/updated timestamp and datetime Generalized support for auto-updated and/or auto-initialized timestamp and datetime columns. This patch is a reimplementation of MySQL's "WL#5874: CURRENT_TIMESTAMP as DEFAULT for DATETIME columns". In order to ease future merges, this implementation reused few function and variable names from MySQL's patch, however the implementation is quite different. TODO: The only unresolved problem in this patch is the semantics of LOAD DATA for TIMESTAMP and DATETIME columns in the cases when there are missing or NULL columns. I couldn't fully comprehend the logic behind MySQL's behavior and its relationship with their own documentation, so I left the results to be more consistent with all other LOAD cases. The problematic test cases can be seen by running the test file function_defaults, and observing the test case differences. Those were left on purpose for discussion.
2012-10-17 14:43:56 +02:00
bool fill_record_n_invoke_before_triggers(THD *thd, TABLE *table,
Field **field,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
List<Item> &values,
bool ignore_errors,
enum trg_event_type event);
bool insert_fields(THD *thd, Name_resolution_context *context,
const char *db_name, const char *table_name,
MDEV-14695: Assertion `n < m_size' failed in Bounds_checked_array<Element_type>::operator In this issue we hit the assert because we are adding addition fields to the field JOIN::all_fields list. This is done because HEAP tables can't index BIT fields so we need to use an additional hidden field for grouping because later it will be converted to a LONG field. Original field will remain of the BIT type and will be returned. This happens when we convert DISTINCT to GROUP BY. The solution is to take into account the number of such hidden fields that would be added to the field JOIN::all_fields list while calculating the size of the ref_pointer_array.
2018-05-14 22:14:03 +02:00
List_iterator<Item> *it, bool any_privileges,
uint *hidden_bit_fields);
MDEV-7951 - sql_alloc() takes 0.25% in OLTP RO sql_alloc() has additional costs compared to direct mem_root allocation: - function call: it is defined in a separate translation unit and can't be inlined - it needs to call pthread_getspecific() to get THD::mem_root It is called dozens of times implicitely at least by: - List<>::push_back() - List<>::push_front() - new (for Sql_alloc derived classes) - sql_memdup() Replaced lots of implicit sql_alloc() calls with direct mem_root allocation, passing through THD pointer whenever it is needed. Number of sql_alloc() calls reduced 345 -> 41 per OLTP RO transaction. pthread_getspecific() overhead dropped 0.76 -> 0.59 sql_alloc() overhed dropped 0.25 -> 0.06
2015-04-17 12:30:15 +02:00
void make_leaves_list(THD *thd, List<TABLE_LIST> &list, TABLE_LIST *tables,
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
bool full_table_list, TABLE_LIST *boundary);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
int setup_wild(THD *thd, TABLE_LIST *tables, List<Item> &fields,
MDEV-14695: Assertion `n < m_size' failed in Bounds_checked_array<Element_type>::operator In this issue we hit the assert because we are adding addition fields to the field JOIN::all_fields list. This is done because HEAP tables can't index BIT fields so we need to use an additional hidden field for grouping because later it will be converted to a LONG field. Original field will remain of the BIT type and will be returned. This happens when we convert DISTINCT to GROUP BY. The solution is to take into account the number of such hidden fields that would be added to the field JOIN::all_fields list while calculating the size of the ref_pointer_array.
2018-05-14 22:14:03 +02:00
List<Item> *sum_func_list, uint wild_num, uint * hidden_bit_fields);
This is the consolidated patch for mdev-8646: "Re-factor the code for post-join operations". The patch mainly contains the code ported from mysql-5.6 and created for two essential architectural changes: 1. WL#5558: Resolve ORDER BY execution method at the optimization stage 2. WL#6071: Inline tmp tables into the nested loops algorithm The first task was implemented for mysql-5.6 by Ole John Aske. It allows to make all decisions on ORDER BY operation at the optimization stage. The second task implemented for mysql-5.6 by Evgeny Potemkin adds JOIN_TAB nodes for post-join operations that require temporary tables. It allows to execute these operations within the nested loops algorithm that used to be used before this task only for join queries. Besides these task moves all planning on the execution of these operations from the execution phase to the optimization phase. Some other re-factoring changes of mysql-5.6 were pulled in, mainly because it was easier to pull them in than roll them back. In particular all changes concerning Ref_ptr_array were incorporated. The port required some changes in the MariaDB code that concerned the functionality of EXPLAIN and ANALYZE. This was done mainly by Sergey Petrunia.
2016-02-09 21:35:59 +01:00
bool setup_fields(THD *thd, Ref_ptr_array ref_pointer_array,
cleanup: renames enum_mark_columns -> enum_column_usage mark_used_columns -> column_usage further commits will replace MARK_COLUMN_NONE with COLUMN_READ and COLUMN_WRITE that convey the intention without causing columns to be marked
2018-02-09 19:43:42 +01:00
List<Item> &item, enum_column_usage column_usage,
MDEV-9619: Assertion `null_ref_table' failed in virtual table_map Item_direct_view_ref::used_tables() const on 2nd execution of PS Refer left expression indirectly in case it changes from execution to execution.
2017-02-18 17:47:31 +01:00
List<Item> *sum_func_list, List<Item> *pre_fix,
bool allow_sum_func);
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
void unfix_fields(List<Item> &items);
Applied all changes from Igor and Sanja
2013-06-15 17:32:08 +02:00
bool fill_record(THD * thd, TABLE *table_arg, List<Item> &fields,
MDEV-7563 Support CHECK constraint as in (or close to) SQL Standard MDEV-10134 Add full support for DEFAULT - Added support for using tables with MySQL 5.7 virtual fields, including MySQL 5.7 syntax - Better error messages also for old cases - CREATE ... SELECT now also updates timestamp columns - Blob can now have default values - Added new system variable "check_constraint_checks", to turn of CHECK constraint checking if needed. - Removed some engine independent tests in suite vcol to only test myisam - Moved some tests from 'include' to 't'. Should some day be done for all tests. - FRM version increased to 11 if one uses virtual fields or constraints - Changed to use a bitmap to check if a field has got a value, instead of setting HAS_EXPLICIT_VALUE bit in field flags - Expressions can now be up to 65K in total - Ensure we are not refering to uninitialized fields when handling virtual fields or defaults - Changed check_vcol_func_processor() to return a bitmap of used types - Had to change some functions that calculated cached value in fix_fields to do this in val() or getdate() instead. - store_now_in_TIME() now takes a THD argument - fill_record() now updates default values - Add a lookahead for NOT NULL, to be able to handle DEFAULT 1+1 NOT NULL - Automatically generate a name for constraints that doesn't have a name - Added support for ALTER TABLE DROP CONSTRAINT - Ensure that partition functions register virtual fields used. This fixes some bugs when using virtual fields in a partitioning function
2016-06-29 09:14:22 +02:00
List<Item> &values, bool ignore_errors, bool update);
MDEV-452 Add full support for auto-initialized/updated timestamp and datetime Generalized support for auto-updated and/or auto-initialized timestamp and datetime columns. This patch is a reimplementation of MySQL's "WL#5874: CURRENT_TIMESTAMP as DEFAULT for DATETIME columns". In order to ease future merges, this implementation reused few function and variable names from MySQL's patch, however the implementation is quite different. TODO: The only unresolved problem in this patch is the semantics of LOAD DATA for TIMESTAMP and DATETIME columns in the cases when there are missing or NULL columns. I couldn't fully comprehend the logic behind MySQL's behavior and its relationship with their own documentation, so I left the results to be more consistent with all other LOAD cases. The problematic test cases can be seen by running the test file function_defaults, and observing the test case differences. Those were left on purpose for discussion.
2012-10-17 14:43:56 +02:00
bool fill_record(THD *thd, TABLE *table, Field **field, List<Item> &values,
merge. checkpoint. does not compile.
2010-11-25 18:17:28 +01:00
bool ignore_errors, bool use_value);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
Field *
find_field_in_tables(THD *thd, Item_ident *item,
TABLE_LIST *first_table, TABLE_LIST *last_table,
Item **ref, find_item_error_report_type report_error,
bool check_privileges, bool register_tree_change);
Field *
find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
MDEV-15091 : Windows, 64bit: reenable and fix warning C4267 (conversion from 'size_t' to 'type', possible loss of data) Handle string length as size_t, consistently (almost always:)) Change function prototypes to accept size_t, where in the past ulong or uint were used. change local/member variables to size_t when appropriate. This fix excludes rocksdb, spider,spider, sphinx and connect for now.
2018-02-06 13:55:58 +01:00
const char *name, size_t length,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
const char *item_name, const char *db_name,
const char *table_name, Item **ref,
bool check_privileges, bool allow_rowid,
uint *cached_field_index_ptr,
bool register_tree_change, TABLE_LIST **actual_table);
Field *
MDEV-15091 : Windows, 64bit: reenable and fix warning C4267 (conversion from 'size_t' to 'type', possible loss of data) Handle string length as size_t, consistently (almost always:)) Change function prototypes to accept size_t, where in the past ulong or uint were used. change local/member variables to size_t when appropriate. This fix excludes rocksdb, spider,spider, sphinx and connect for now.
2018-02-06 13:55:58 +01:00
find_field_in_table(THD *thd, TABLE *table, const char *name, size_t length,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
bool allow_rowid, uint *cached_field_index_ptr);
Field *
find_field_in_table_sef(TABLE *table, const char *name);
Item ** find_item_in_list(Item *item, List<Item> &items, uint *counter,
find_item_error_report_type report_error,
Fixed bug mdev-9897. This bug revealed a serious problem: if the same partition list was used in two window specifications then the temporary table created to calculate window functions contained fields for two identical partitions. This problem was fixed as well.
2016-04-14 09:47:28 +02:00
enum_resolution_type *resolution, uint limit= 0);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
bool setup_tables(THD *thd, Name_resolution_context *context,
List<TABLE_LIST> *from_clause, TABLE_LIST *tables,
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
List<TABLE_LIST> &leaves, bool select_insert,
bool full_table_list);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
bool setup_tables_and_check_access(THD *thd,
Name_resolution_context *context,
List<TABLE_LIST> *from_clause,
TABLE_LIST *tables,
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
List<TABLE_LIST> &leaves,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
bool select_insert,
ulong want_access_first,
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
ulong want_access,
bool full_table_list);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
bool wait_while_table_is_used(THD *thd, TABLE *table,
MDEV-4786 merge 10.0-monty -> 10.0 remove TDC_RT_REMOVE_NOT_OWN_AND_MARK_NOT_USABLE
2013-08-12 15:46:35 +02:00
enum ha_extra_function function);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
Changed database, tablename and alias to be LEX_CSTRING This was done in, among other things: - thd->db and thd->db_length - TABLE_LIST tablename, db, alias and schema_name - Audit plugin database name - lex->db - All db and table names in Alter_table_ctx - st_select_lex db Other things: - Changed a lot of functions to take const LEX_CSTRING* as argument for db, table_name and alias. See init_one_table() as an example. - Changed some function arguments from LEX_CSTRING to const LEX_CSTRING - Changed some lists from LEX_STRING to LEX_CSTRING - threads_mysql.result changed because process list_db wasn't always correctly updated - New append_identifier() function that takes LEX_CSTRING* as arguments - Added new element tmp_buff to Alter_table_ctx to separate temp name handling from temporary space - Ensure we store the length after my_casedn_str() of table/db names - Removed not used version of rename_table_in_stat_tables() - Changed Natural_join_column::table_name and db_name() to never return NULL (used for print) - thd->get_db() now returns db as a printable string (thd->db.str or "")
2018-01-07 17:03:44 +01:00
void drop_open_table(THD *thd, TABLE *table, const LEX_CSTRING *db_name,
const LEX_CSTRING *table_name);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
void update_non_unique_table_error(TABLE_LIST *update,
const char *operation,
TABLE_LIST *duplicate);
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
COND **conds);
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
void wrap_ident(THD *thd, Item **conds);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
int setup_ftfuncs(SELECT_LEX* select);
MDEV-15465 Server crash or ASAN heap-use-after-free in Item_func_match::cleanup upon using FT search with partitioning. Partition engine FT keys are implemented in such a way that the FT function's cleanup() methods use table's internals. So calling them after close_thread_tables is unsafe.
2018-05-15 12:10:19 +02:00
void cleanup_ftfuncs(SELECT_LEX *select_lex);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
int init_ftfuncs(THD *thd, SELECT_LEX* select, bool no_order);
MDEV-7112 Split HA_CREATE_INFO
2014-12-08 07:56:08 +01:00
bool lock_table_names(THD *thd, const DDL_options_st &options,
TABLE_LIST *table_list,
A 5.5 version of the fix for Bug #54360 "Deadlock DROP/ALTER/CREATE DATABASE with open HANDLER" Remove LOCK_create_db, database name locks, and use metadata locks instead. This exposes CREATE/DROP/ALTER DATABASE statements to the graph-based deadlock detector in MDL, and paves the way for a safe, deadlock-free implementation of RENAME DATABASE. Database DDL statements will now take exclusive metadata locks on the database name, while table/view/routine DDL statements take intention exclusive locks on the database name. This prevents race conditions between database DDL and table/view/routine DDL. (e.g. DROP DATABASE with concurrent CREATE/ALTER/DROP TABLE) By adding database name locks, this patch implements WL#4450 "DDL locking: CREATE/DROP DATABASE must use database locks" and WL#4985 "DDL locking: namespace/hierarchical locks". The patch also changes code to use init_one_table() where appropriate. The new lock_table_names() function requires TABLE_LIST::db_length to be set correctly, and this is taken care of by init_one_table(). This patch also adds a simple template to help work with the mysys HASH data structure. Most of the patch was written by Konstantin Osipov.
2010-07-01 15:53:46 +02:00
TABLE_LIST *table_list_end, ulong lock_wait_timeout,
uint flags);
MDEV-7112 Split HA_CREATE_INFO
2014-12-08 07:56:08 +01:00
static inline bool
lock_table_names(THD *thd, TABLE_LIST *table_list,
TABLE_LIST *table_list_end, ulong lock_wait_timeout,
uint flags)
{
return lock_table_names(thd, thd->lex->create_info, table_list,
table_list_end, lock_wait_timeout, flags);
}
bool open_tables(THD *thd, const DDL_options_st &options,
Merge branch '5.5' into 10.1
2019-04-26 14:02:37 +02:00
TABLE_LIST **tables, uint *counter,
Merge branch '5.5' into 10.1
2019-06-12 22:54:46 +02:00
uint flags, Prelocking_strategy *prelocking_strategy);
Merge branch '5.5' into 10.1
2019-04-26 14:02:37 +02:00
MDEV-7112 Split HA_CREATE_INFO
2014-12-08 07:56:08 +01:00
static inline bool
open_tables(THD *thd, TABLE_LIST **tables, uint *counter, uint flags,
Prelocking_strategy *prelocking_strategy)
{
return open_tables(thd, thd->lex->create_info, tables, counter, flags,
prelocking_strategy);
}
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
/* open_and_lock_tables with optional derived handling */
MDEV-7112 Split HA_CREATE_INFO
2014-12-08 07:56:08 +01:00
bool open_and_lock_tables(THD *thd, const DDL_options_st &options,
TABLE_LIST *tables,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
bool derived, uint flags,
Prelocking_strategy *prelocking_strategy);
MDEV-7112 Split HA_CREATE_INFO
2014-12-08 07:56:08 +01:00
static inline bool
open_and_lock_tables(THD *thd, TABLE_LIST *tables,
bool derived, uint flags,
Prelocking_strategy *prelocking_strategy)
{
return open_and_lock_tables(thd, thd->lex->create_info,
tables, derived, flags, prelocking_strategy);
}
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
/* simple open_and_lock_tables without derived handling for single table */
TABLE *open_n_lock_single_table(THD *thd, TABLE_LIST *table_l,
Fix for bug #56251 "Deadlock with INSERT DELAYED and MERGE tables". Attempting to issue an INSERT DELAYED statement for a MERGE table might have caused a deadlock if it happened as part of a transaction or under LOCK TABLES, and there was a concurrent DDL or LOCK TABLES ... WRITE statement which tried to lock one of its underlying tables. The problem occurred when a delayed insert handler thread tried to open a MERGE table and discovered that to do this it had also to open all underlying tables and hence acquire metadata locks on them. Since metadata locks on the underlying tables were not pre-acquired by the connection thread executing INSERT DELAYED, attempts to do so might lead to waiting. In this case the connection thread had to wait for the delayed insert thread. If the thread which was preventing the lock on the underlying table from being acquired had to wait for the connection thread (due to this or other metadata locks), a deadlock occurred. This deadlock was not detected by the MDL deadlock detector since waiting for the handler thread by the connection thread is not represented in the wait-for graph. This patch solves the problem by ensuring that the delayed insert handler thread never tries to open underlying tables of a MERGE table. Instead open_tables() is aborted right after the parent table is opened and a ER_DELAYED_NOT_SUPPORTED error is emitted (which is passed to the connection thread and ultimately to the user). mysql-test/r/merge.result: Added test for bug #56251 "Deadlock with INSERT DELAYED and MERGE tables". mysql-test/t/merge.test: Added test for bug #56251 "Deadlock with INSERT DELAYED and MERGE tables". sql/sql_base.cc: Changed open_n_lock_single_table() to take prelocking strategy as an argument instead of always using DML_prelocking_strategy. sql/sql_base.h: Changed open_n_lock_single_table() to take prelocking strategy as an argument instead of always using DML_prelocking_strategy. Added a version of this function which is compatible with old signature. sql/sql_insert.cc: When opening MERGE table in delayed insert thread stop and emit ER_DELAYED_NOT_SUPPORTED right after opening main table and before opening underlying tables. This ensures that we won't try to acquire metadata lock on underlying tables which might lead to a deadlock. This is achieved by using special prelocking strategy which abort open_tables() process as soon as we discover that we have opened table with engine which doesn't support delayed inserts.
2010-09-15 16:15:31 +02:00
thr_lock_type lock_type, uint flags,
Prelocking_strategy *prelocking_strategy);
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
bool open_normal_and_derived_tables(THD *thd, TABLE_LIST *tables, uint flags,
uint dt_phases);
MDEV-10577 sql_mode=ORACLE: %TYPE in variable declarations
2016-12-06 06:05:52 +01:00
bool open_tables_only_view_structure(THD *thd, TABLE_LIST *tables,
bool can_deadlock);
MDEV 13679 Enabled sequences to be used in DEFAULT Other changes done to get this to work: - Added 'internal_tables' to TABLE object to list which sequence tables is needed to use the table. - Mark any expression using DEFAULT() with LEX->default_used. This is needed when deciding if we should open internal sequence tables when a table is opened (we don't need to open sequence tables if the main table is only used with SELECT). - Create_and_open_temporary_table() can now also open all internal sequence tables. - Added option MYSQL_LOCK_USE_MALLOC to mysql_lock_tables() to force memory allocation to be used with malloc instead of memroot. - Added flag to MYSQL_LOCK to remember if allocation was done with malloc or memroot (makes code simpler and safer). - init_one_table_for_prelocking() now takes argument for what lock to use instead of it's a routine or something else. - Renamed prelocking placeholders to make them more understandable as they are now used in more code. - Changed test in check_lock_and_start_stmt() if found table has correct locks. The old test didn't work for tables that has lock TL_WRITE_ALLOW_WRITE, which is what sequence tables are using. - Added VCOL_NOT_VIRTUAL option to ensure that sequence functions can't be used with virtual columns - More sequence tests
2017-12-22 13:56:09 +01:00
bool open_and_lock_internal_tables(TABLE *table, bool lock);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
bool lock_tables(THD *thd, TABLE_LIST *tables, uint counter, uint flags);
int decide_logging_format(THD *thd, TABLE_LIST *tables);
Applied all changes from Igor and Sanja
2013-06-15 17:32:08 +02:00
void close_thread_table(THD *thd, TABLE **table_ptr);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
TABLE_LIST *unique_table(THD *thd, TABLE_LIST *table, TABLE_LIST *table_list,
MDEV-11129 CREATE OR REPLACE TABLE t1 AS SELECT spfunc() crashes if spfunc() references t1 Fixed by extending unique_table() with a flag to not allow usage of the replaced table. I also cleaned up find_dup_table() to not use goto next. I also added more comments to the code in find_dup_table()
2018-05-16 20:51:46 +02:00
uint check_flag);
Changing field::field_name and Item::name to LEX_CSTRING Benefits of this patch: - Removed a lot of calls to strlen(), especially for field_string - Strings generated by parser are now const strings, less chance of accidently changing a string - Removed a lot of calls with LEX_STRING as parameter (changed to pointer) - More uniform code - Item::name_length was not kept up to date. Now fixed - Several bugs found and fixed (Access to null pointers, access of freed memory, wrong arguments to printf like functions) - Removed a lot of casts from (const char*) to (char*) Changes: - This caused some ABI changes - lex_string_set now uses LEX_CSTRING - Some fucntions are now taking const char* instead of char* - Create_field::change and after changed to LEX_CSTRING - handler::connect_string, comment and engine_name() changed to LEX_CSTRING - Checked printf() related calls to find bugs. Found and fixed several errors in old code. - A lot of changes from LEX_STRING to LEX_CSTRING, especially related to parsing and events. - Some changes from LEX_STRING and LEX_STRING & to LEX_CSTRING* - Some changes for char* to const char* - Added printf argument checking for my_snprintf() - Introduced null_clex_str, star_clex_string, temp_lex_str to simplify code - Added item_empty_name and item_used_name to be able to distingush between items that was given an empty name and items that was not given a name This is used in sql_yacc.yy to know when to give an item a name. - select table_name."*' is not anymore same as table_name.* - removed not used function Item::rename() - Added comparision of item->name_length before some calls to my_strcasecmp() to speed up comparison - Moved Item_sp_variable::make_field() from item.h to item.cc - Some minimal code changes to avoid copying to const char * - Fixed wrong error message in wsrep_mysql_parse() - Fixed wrong code in find_field_in_natural_join() where real_item() was set when it shouldn't - ER_ERROR_ON_RENAME was used with extra arguments. - Removed some (wrong) ER_OUTOFMEMORY, as alloc_root will already give the error. TODO: - Check possible unsafe casts in plugin/auth_examples/qa_auth_interface.c - Change code to not modify LEX_CSTRING for database name (as part of lower_case_table_names)
2017-04-23 18:39:57 +02:00
bool is_equal(const LEX_CSTRING *a, const LEX_CSTRING *b);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
MDEV-506 Cassandra dynamic columns access
2012-09-28 14:27:16 +02:00
class Open_tables_backup;
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
/* Functions to work with system tables. */
bool open_system_tables_for_read(THD *thd, TABLE_LIST *table_list,
Open_tables_backup *backup);
void close_system_tables(THD *thd, Open_tables_backup *backup);
A pre-requisite patch for the fix for Bug#52044. This patch also fixes Bug#55452 "SET PASSWORD is replicated twice in RBR mode". The goal of this patch is to remove the release of metadata locks from close_thread_tables(). This is necessary to not mistakenly release the locks in the course of a multi-step operation that involves multiple close_thread_tables() or close_tables_for_reopen(). On the same token, move statement commit outside close_thread_tables(). Other cleanups: Cleanup COM_FIELD_LIST. Don't call close_thread_tables() in COM_SHUTDOWN -- there are no open tables there that can be closed (we leave the locked tables mode in THD destructor, and this close_thread_tables() won't leave it anyway). Make open_and_lock_tables() and open_and_lock_tables_derived() call close_thread_tables() upon failure. Remove the calls to close_thread_tables() that are now unnecessary. Simplify the back off condition in Open_table_context. Streamline metadata lock handling in LOCK TABLES implementation. Add asserts to ensure correct life cycle of statement transaction in a session. Remove a piece of dead code that has also become redundant after the fix for Bug 37521. mysql-test/r/variables.result: Update results: set @@autocommit and statement transaction/ prelocked mode. mysql-test/r/view.result: A harmless change in CHECK TABLE <view> status for a broken view. If previously a failure to prelock all functions used in a view would leave the connection in LTM_PRELOCKED mode, now we call close_thread_tables() from open_and_lock_tables() and leave prelocked mode, thus some check in mysql_admin_table() that works only in prelocked/locked tables mode is no longer activated. mysql-test/suite/rpl/r/rpl_row_implicit_commit_binlog.result: Fixed Bug#55452 "SET PASSWORD is replicated twice in RBR mode": extra binlog events are gone from the binary log. mysql-test/t/variables.test: Add a test case: set autocommit and statement transaction/prelocked mode. sql/event_data_objects.cc: Simplify code in Event_job_data::execute(). Move sp_head memory management to lex_end(). sql/event_db_repository.cc: Move the release of metadata locks outside close_thread_tables(). Make sure we call close_thread_tables() when open_and_lock_tables() fails and remove extra code from the events data dictionary. Use close_mysql_tables(), a new internal function to properly close mysql.* tables in the data dictionary. Contract Event_db_repository::drop_events_by_field, drop_schema_events into one function. When dropping all events in a schema, make sure we don't mistakenly release all locks acquired by DROP DATABASE. These include locks on the database name and the global intention exclusive metadata lock. sql/event_db_repository.h: Function open_event_table() does not require an instance of Event_db_repository. sql/events.cc: Use close_mysql_tables() instead of close_thread_tables() to bootstrap events, since the latter no longer releases metadata locks. sql/ha_ndbcluster.cc: - mysql_rm_table_part2 no longer releases acquired metadata locks. Do it in the caller. sql/ha_ndbcluster_binlog.cc: Deploy the new protocol for closing thread tables in run_query() and ndb_binlog_index code. sql/handler.cc: Assert that we never call ha_commit_trans/ ha_rollback_trans in sub-statement, which is now the case. sql/handler.h: Add an accessor to check whether THD_TRANS object is empty (has no transaction started). sql/log.cc: Update a comment. sql/log_event.cc: Since now we commit/rollback statement transaction in mysql_execute_command(), we need a mechanism to communicate from Query_log_event::do_apply_event() to mysql_execute_command() that the statement transaction should be rolled back, not committed. Ideally it would be a virtual method of THD. I hesitate to make THD a virtual base class in this already large patch. Use a thd->variables.option_bits for now. Remove a call to close_thread_tables() from the slave IO thread. It doesn't open any tables, and the protocol for closing thread tables is more complicated now. Make sure we properly close thread tables, however, in Load_data_log_event, which doesn't follow the standard server execution procedure with mysql_execute_command(). @todo: this piece should use Server_runnable framework instead. Remove an unnecessary call to mysql_unlock_tables(). sql/rpl_rli.cc: Update Relay_log_info::slave_close_thread_tables() to follow the new close protocol. sql/set_var.cc: Remove an unused header. sql/slave.cc: Remove an unnecessary call to close_thread_tables(). sql/sp.cc: Remove unnecessary calls to close_thread_tables() from SP DDL implementation. The tables will be closed by the caller, in mysql_execute_command(). When dropping all routines in a database, make sure to not mistakenly drop all metadata locks acquired so far, they include the scoped lock on the schema. sql/sp_head.cc: Correct the protocol that closes thread tables in an SP instruction. Clear lex->sphead before cleaning up lex with lex_end to make sure that we don't delete the sphead twice. It's considered to be "cleaner" and more in line with future changes than calling delete lex->sphead in other places that cleanup the lex. sql/sp_head.h: When destroying m_lex_keeper of an instruction, don't delete the sphead that all lex objects share. @todo: don't store a reference to routine's sp_head instance in instruction's lex. sql/sql_acl.cc: Don't call close_thread_tables() where the caller will do that for us. Fix Bug#55452 "SET PASSWORD is replicated twice in RBR mode" by disabling RBR replication in change_password() function. Use close_mysql_tables() in bootstrap and ACL reload code to make sure we release all metadata locks. sql/sql_base.cc: This is the main part of the patch: - remove manipulation with thd->transaction and thd->mdl_context from close_thread_tables(). Now this function is only responsible for closing tables, nothing else. This is necessary to be able to easily use close_thread_tables() in procedures, that involve multiple open/close tables, which all need to be protected continuously by metadata locks. Add asserts ensuring that TABLE object is only used when is protected by a metadata lock. Simplify the back off condition of Open_table_context, we no longer need to look at the autocommit mode. Make open_and_lock_tables() and open_normal_and_derived_tables() close thread tables and release metadata locks acquired so-far upon failure. This simplifies their usage. Implement close_mysql_tables(). sql/sql_base.h: Add declaration for close_mysql_tables(). sql/sql_class.cc: Remove a piece of dead code that has also become redundant after the fix for Bug 37521. The code became dead when my_eof() was made a non-protocol method, but a method that merely modifies the diagnostics area. The code became redundant with the fix for Bug#37521, when we started to cal close_thread_tables() before Protocol::end_statement(). sql/sql_do.cc: Do nothing in DO if inside a substatement (the assert moved out of trans_rollback_stmt). sql/sql_handler.cc: Add comments. sql/sql_insert.cc: Remove dead code. Release metadata locks explicitly at the end of the delayed insert thread. sql/sql_lex.cc: Add destruction of lex->sphead to lex_end(), lex "reset" method called at the end of each statement. sql/sql_parse.cc: Move close_thread_tables() and other related cleanups to mysql_execute_command() from dispatch_command(). This has become possible after the fix for Bug#37521. Mark federated SERVER statements as DDL. Next step: make sure that we don't store eof packet in the query cache, and move the query cache code outside mysql_parse. Brush up the code of COM_FIELD_LIST. Remove unnecessary calls to close_thread_tables(). When killing a query, don't report "OK" if it was a suicide. sql/sql_parse.h: Remove declaration of a function that is now static. sql/sql_partition.cc: Remove an unnecessary call to close_thread_tables(). sql/sql_plugin.cc: open_and_lock_tables() will clean up after itself after a failure. Move close_thread_tables() above end: label, and replace with close_mysql_tables(), which will also release the metadata lock on mysql.plugin. sql/sql_prepare.cc: Now that we no longer release locks in close_thread_tables() statement prepare code has become more straightforward. Remove the now redundant check for thd->killed() (used only by the backup project) from Execute_server_runnable. Reorder code to take into account that now mysql_execute_command() performs lex->unit.cleanup() and close_thread_tables(). sql/sql_priv.h: Add a new option to server options to interact between the slave SQL thread and execution framework (hack). @todo: use a virtual method of class THD instead. sql/sql_servers.cc: Due to Bug 25705 replication of DROP/CREATE/ALTER SERVER is broken. Make sure at least we do not attempt to replicate these statements using RBR, as this violates the assert in close_mysql_tables(). sql/sql_table.cc: Do not release metadata locks in mysql_rm_table_part2, this is done by the caller. Do not call close_thread_tables() in mysql_create_table(), this is done by the caller. Fix a bug in DROP TABLE under LOCK TABLES when, upon error in wait_while_table_is_used() we would mistakenly release the metadata lock on a non-dropped table. Explicitly release metadata locks when doing an implicit commit. sql/sql_trigger.cc: Now that we delete lex->sphead in lex_end(), zero the trigger's sphead in lex after loading the trigger, to avoid double deletion. sql/sql_udf.cc: Use close_mysql_tables() instead of close_thread_tables(). sql/sys_vars.cc: Remove code added in scope of WL#4284 which would break when we perform set @@session.autocommit along with setting other variables and using tables or functions. A test case added to variables.test. sql/transaction.cc: Add asserts. sql/tztime.cc: Use close_mysql_tables() rather than close_thread_tables().
2010-07-27 12:25:53 +02:00
void close_mysql_tables(THD *thd);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
TABLE *open_system_table_for_update(THD *thd, TABLE_LIST *one_table);
TABLE *open_log_table(THD *thd, TABLE_LIST *one_table, Open_tables_backup *backup);
void close_log_table(THD *thd, Open_tables_backup *backup);
Commit on behalf of Dmitry Lenev. Merge his patch for Bug#52044 into 5.5, and apply review comments.
2010-08-12 15:50:23 +02:00
bool close_cached_tables(THD *thd, TABLE_LIST *tables,
Fix for bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". The problem was that FLUSH TABLES <list> WITH READ LOCK which was issued when other connection has acquired global read lock using FLUSH TABLES WITH READ LOCK was blocked and has to wait until global read lock is released. This issue stemmed from the fact that FLUSH TABLES <list> WITH READ LOCK implementation has acquired X metadata locks on tables to be flushed. Since these locks required acquiring of global IX lock this statement was incompatible with global read lock. This patch addresses problem by using SNW metadata type of lock for tables to be flushed by FLUSH TABLES <list> WITH READ LOCK. It is OK to acquire them without global IX lock as long as we won't try to upgrade those locks. Since SNW locks allow concurrent statements using same table FLUSH TABLE <list> WITH READ LOCK now has to wait until old versions of tables to be flushed go away after acquiring metadata locks. Since such waiting can lead to deadlock MDL deadlock detector was extended to take into account waits for flush and resolve such deadlocks. As a bonus code in open_tables() which was responsible for waiting old versions of tables to go away was refactored. Now when we encounter old version of table in open_table() we don't back-off and wait for all old version to go away, but instead wait for this particular table to be flushed. Such approach supported by deadlock detection should reduce number of scenarios in which FLUSH TABLES aborts concurrent multi-statement transactions. Note that active FLUSH TABLES <list> WITH READ LOCK still blocks concurrent FLUSH TABLES WITH READ LOCK statement as the former keeps tables open and thus prevents the latter statement from doing flush. mysql-test/include/handler.inc: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/r/flush.result: Added test which checks that "flush tables <list> with read lock" is compatible with active "flush tables with read lock" but not vice-versa. This test also covers bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". mysql-test/r/mdl_sync.result: Added scenarios in which wait for table to be flushed causes deadlocks to the coverage of MDL deadlock detector. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Adjusted test results after removal of COND_refresh condition variable. mysql-test/suite/perfschema/r/server_init.result: Adjusted test and its results after removal of COND_refresh condition variable. mysql-test/suite/perfschema/t/server_init.test: Adjusted test and its results after removal of COND_refresh condition variable. mysql-test/t/flush.test: Added test which checks that "flush tables <list> with read lock" is compatible with active "flush tables with read lock" but not vice-versa. This test also covers bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". mysql-test/t/kill.test: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/t/lock_multi.test: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/t/mdl_sync.test: Added scenarios in which wait for table to be flushed causes deadlocks to the coverage of MDL deadlock detector. sql/ha_ndbcluster.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/ha_ndbcluster_binlog.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/lock.cc: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/mdl.cc: Now MDL deadlock detector takes into account information about waits for table flushes when searching for deadlock. To implement this change: - Declaration of enum_deadlock_weight and Deadlock_detection_visitor were moved to mdl.h header to make them available to the code in table.cc which implements deadlock detector traversal through edges of waiters graph representing waiting for flush. - Since now MDL_context may wait not only for metadata lock but also for table to be flushed an abstract Wait_for_edge class was introduced. Its descendants MDL_ticket and Flush_ticket incapsulate specifics of inspecting waiters graph when following through edge representing wait of particular type. We no longer require global IX metadata lock when acquiring SNW or SNRW locks. Such locks are needed only when metadata locks of these types are upgraded to X locks. This allows to use SNW locks in FLUSH TABLES <list> WITH READ LOCK implementation and keep the latter compatible with global read lock. sql/mdl.h: Now MDL deadlock detector takes into account information about waits for table flushes when searching for deadlock. To implement this change: - Declaration of enum_deadlock_weight and Deadlock_detection_visitor were moved to mdl.h header to make them available to the code in table.cc which implements deadlock detector traversal through edges of waiters graph representing waiting for flush. - Since now MDL_context may wait not only for metadata lock but also for table to be flushed an abstract Wait_for_edge class was introduced. Its descendants MDL_ticket and Flush_ticket incapsulate specifics of inspecting waiters graph when following through edge representing wait of particular type. - Deadlock_detection_visitor now has m_table_shares_visited member which allows to support recursive locking for LOCK_open. This is required when deadlock detector inspects waiters graph which contains several edges representing waits for flushes or needs to come through the such edge more than once. sql/mysqld.cc: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/mysqld.h: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/sql_base.cc: Changed approach to how threads are waiting for table to be flushed. Now thread that wants to wait for old table to go away subscribes for notification by adding Flush_ticket to table's share and waits using MDL_context::m_wait object. Once table gets flushed (i.e. all tables are closed and table share is ready to be destroyed) all such waiters are notified individually. Thanks to this change MDL deadlock detector can take such waits into account. To implement this/as result of this change: - tdc_wait_for_old_versions() was replaced with tdc_wait_for_old_version() which waits for individual old share to go away and which is called by open_table() after finding out that share is outdated. We don't need to perform back-off before such waiting thanks to the fact that deadlock detector now sees such waits. - As result Open_table_ctx::m_mdl_requests became unnecessary and was removed. We no longer allocate copies of MDL_request objects on MEM_ROOT when MYSQL_OPEN_FORCE_SHARED/SHARED_HIGH_PRIO flags are in effect. - close_cached_tables() and tdc_wait_for_old_version() share code which implements waiting for share to be flushed - the both use TABLE_SHARE::wait_until_flush() method. Thanks to this close_cached_tables() supports timeouts and has extra parameter for this. - Open_table_context::OT_MDL_CONFLICT enum element was renamed to OT_CONFLICT as it is now also used in cases when back-off is required to resolve deadlock caused by waiting for flush and not metadata lock. - In cases when we discover that current connection tries to open tables from different generation we now simply back-off and restart process of opening tables. To support this Open_table_context::OT_REOPEN_TABLES enum element was added. - COND_refresh condition variable became unnecessary and was removed. - mysql_notify_thread_having_shared_lock() no longer wakes up connections waiting for flush as all such connections can be waken up by deadlock detector if necessary. sql/sql_base.h: - close_cached_tables() now has one more parameter - timeout for waiting for table to be flushed. - Open_table_context::OT_MDL_CONFLICT enum element was renamed to OT_CONFLICT as it is now also used in cases when back-off is required to resolve deadlock caused by waiting for flush and not metadata lock. Added new OT_REOPEN_TABLES enum element to be used in cases when we need to restart open tables process even in the middle of transaction. - Open_table_ctx::m_mdl_requests became unnecessary and was removed. sql/sql_class.h: Added assert ensuring that we won't use LOCK_open mutex with THD::enter_cond(). Otherwise deadlocks can arise in MDL deadlock detector. sql/sql_parse.cc: Changed FLUSH TABLES <list> WITH READ LOCK to take SNW metadata locks instead of X locks on tables to be flushed. Since we no longer require global IX lock to be taken when SNW locks are taken this makes this statement compatible with FLUSH TABLES WITH READ LOCK statement. Since SNW locks allow other connections to have table opened FLUSH TABLES <list> WITH READ LOCK now has to wait during open_tables() for old version to go away. Such waits can lead to deadlocks which will be detected by MDL deadlock detector which now takes waits for table to be flushed into account. Also adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/sql_yacc.yy: FLUSH TABLES <list> WITH READ LOCK now needs only SNW metadata locks on tables. sql/sys_vars.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/table.cc: Implemented new approach to how threads are waiting for table to be flushed. Now thread that wants to wait for old table to go away subscribes for notification by adding Flush_ticket to table's share and waits using MDL_context::m_wait object. Once table gets flushed (i.e. all tables are closed and table share is ready to be destroyed) all such waiters are notified individually. This change allows to make such waits visible inside of MDL deadlock detector. To do it: - Added list of waiters/Flush_tickets to TABLE_SHARE class. - Changed free_table_share() to postpone freeing of share memory until last waiter goes away and to wake up subscribed waiters. - Added TABLE_SHARE::wait_until_flushed() method which implements subscription to the list of waiters for table to be flushed and waiting for this event. Implemented interface which allows to expose waits for flushes to MDL deadlock detector: - Introduced Flush_ticket class a descendant of Wait_for_edge class. - Added TABLE_SHARE::find_deadlock() method which allows deadlock detector to find out what contexts are still using old version of table in question (i.e. to find out what contexts are waited for by owner of Flush_ticket). sql/table.h: In order to support new strategy of waiting for table flush (see comment for table.cc for details) added list of waiters/Flush_tickets to TABLE_SHARE class. Implemented interface which allows to expose waits for flushes to MDL deadlock detector: - Introduced Flush_ticket class a descendant of Wait_for_edge class. - Added TABLE_SHARE::find_deadlock() method which allows deadlock detector to find out what contexts are still using old version of table in question (i.e. to find out what contexts are waited for by owner of Flush_ticket).
2010-07-27 15:34:58 +02:00
bool wait_for_refresh, ulong timeout);
Optimize flush tables with read lock (FTWRL) to not wait for select's Part of MDEV-5336 Implement LOCK FOR BACKUP The idea is that instead of waiting in close_cached_tables() for all tables to be closed, we instead call flush_tables() that does: - Flush not used objects in table cache to free memory - Collect all tables that are open - Call HA_EXTRA_FLUSH on the objects, to get them into "closed state" - Added HA_EXTRA_FLUSH support to archive and CSV - Added multi-user protection to HA_EXTRA_FLUSH in MyISAM and Aria The benefit compared to old code is: - FTWRL doesn't have to wait for long running read operations or open HANDLER's
2018-10-09 17:55:18 +02:00
void purge_tables(bool purge_flag);
Added new MDL_BACKUP locks for all backup stages Part of MDEV-5336 Implement LOCK FOR BACKUP - Added new locks to MDL_BACKUP for all stages of backup locks and a new MDL lock needed for backup stages. - Renamed MDL_BACKUP_STMT to MDL_BACKUP_DDL - flush_tables() takes a new parameter that decides what should be flushed. - InnoDB, Aria (transactional tables with checksums), Blackhole, Federated and Federatedx tables are marked to be safe for online backup. We are using MDL_BACKUP_TRANS_DML instead of MDL_BACKUP_DML locks for these which allows any DML's to proceed for these tables during the whole backup process until BACKUP STAGE COMMIT which will block the final commit.
2018-11-06 16:05:24 +01:00
bool flush_tables(THD *thd, flush_tables_type flag);
Changing field::field_name and Item::name to LEX_CSTRING Benefits of this patch: - Removed a lot of calls to strlen(), especially for field_string - Strings generated by parser are now const strings, less chance of accidently changing a string - Removed a lot of calls with LEX_STRING as parameter (changed to pointer) - More uniform code - Item::name_length was not kept up to date. Now fixed - Several bugs found and fixed (Access to null pointers, access of freed memory, wrong arguments to printf like functions) - Removed a lot of casts from (const char*) to (char*) Changes: - This caused some ABI changes - lex_string_set now uses LEX_CSTRING - Some fucntions are now taking const char* instead of char* - Create_field::change and after changed to LEX_CSTRING - handler::connect_string, comment and engine_name() changed to LEX_CSTRING - Checked printf() related calls to find bugs. Found and fixed several errors in old code. - A lot of changes from LEX_STRING to LEX_CSTRING, especially related to parsing and events. - Some changes from LEX_STRING and LEX_STRING & to LEX_CSTRING* - Some changes for char* to const char* - Added printf argument checking for my_snprintf() - Introduced null_clex_str, star_clex_string, temp_lex_str to simplify code - Added item_empty_name and item_used_name to be able to distingush between items that was given an empty name and items that was not given a name This is used in sql_yacc.yy to know when to give an item a name. - select table_name."*' is not anymore same as table_name.* - removed not used function Item::rename() - Added comparision of item->name_length before some calls to my_strcasecmp() to speed up comparison - Moved Item_sp_variable::make_field() from item.h to item.cc - Some minimal code changes to avoid copying to const char * - Fixed wrong error message in wsrep_mysql_parse() - Fixed wrong code in find_field_in_natural_join() where real_item() was set when it shouldn't - ER_ERROR_ON_RENAME was used with extra arguments. - Removed some (wrong) ER_OUTOFMEMORY, as alloc_root will already give the error. TODO: - Check possible unsafe casts in plugin/auth_examples/qa_auth_interface.c - Change code to not modify LEX_CSTRING for database name (as part of lower_case_table_names)
2017-04-23 18:39:57 +02:00
bool close_cached_connection_tables(THD *thd, LEX_CSTRING *connect_string);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
void close_all_tables_for_name(THD *thd, TABLE_SHARE *share,
Applied all changes from Igor and Sanja
2013-06-15 17:32:08 +02:00
ha_extra_function extra,
TABLE *skip_table);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
OPEN_TABLE_LIST *list_open_tables(THD *thd, const char *db, const char *wild);
MDEV-9488 - Table cache cleanups Cleanup now unused arguments of tdc_open_view().
2015-12-29 16:09:11 +01:00
bool tdc_open_view(THD *thd, TABLE_LIST *table_list, uint flags);
convenience helpers for get_table_share() and tdc_open_view(). Pass db and table_name into a function instead of the table_list, when only db and table name are needed.
2013-04-09 15:35:24 +02:00
Bug #11764779 (former 57649) FLUSH TABLES under FLUSH TABLES <list> WITH READ LOCK leads to assert failure. This assert was triggered if a statement tried up upgrade a metadata lock with an active FLUSH TABLE <list> WITH READ LOCK. The assert checks that the connection already holds a global intention exclusive metadata lock. However, FLUSH TABLE <list> WITH READ LOCK does not acquire this lock in order to be compatible with FLUSH TABLES WITH READ LOCK. Therefore any metadata lock upgrade caused the assert to be triggered. This patch fixes the problem by preventing metadata lock upgrade if the connection has an active FLUSH TABLE <list> WITH READ LOCK. ER_TABLE_NOT_LOCKED_FOR_WRITE will instead be reported to the client. Test case added to flush.test.
2011-03-07 10:08:10 +01:00
TABLE *find_table_for_mdl_upgrade(THD *thd, const char *db,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
const char *table_name,
MDEV-15890 Strange error message if you try to FLUSH TABLES <view> after LOCK TABLES <view>. Check if the argument of the FLUSH TABLE is a VIEW and handle it accordingly.
2018-09-02 07:24:33 +02:00
int *p_error);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
void mark_tmp_table_for_reuse(TABLE *table);
* remove ha_check_if_table_exists() and get_table_share_with_discover(). * rename check_if_table_exists() -> table_exists() and remove unneeded arguments
2013-04-09 15:35:15 +02:00
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
int dynamic_column_error_message(enum_dyncol_func_result rc);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
Merge maria-5.3-mwl248 -> 5.5 = maria-5.5-mwl248.
2012-03-19 09:35:32 +01:00
/* open_and_lock_tables with optional derived handling */
int open_and_lock_tables_derived(THD *thd, TABLE_LIST *tables, bool derived);
extern "C" int simple_raw_key_cmp(void* arg, const void* key1,
const void* key2);
extern "C" int count_distinct_walk(void *elem, element_count count, void *arg);
int simple_str_key_cmp(void* arg, uchar* key1, uchar* key2);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
extern Item **not_found_item;
extern Field *not_found_field;
extern Field *view_ref_found;
/**
clean/setup table fields and map.
@param table TABLE structure pointer (which should be setup)
@param table_list TABLE_LIST structure pointer (owner of TABLE)
@param tablenr table number
*/
inline void setup_table_map(TABLE *table, TABLE_LIST *table_list, uint tablenr)
{
table->used_fields= 0;
merge with 5.3 sql/sql_insert.cc: CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. ****** CREATE ... IF NOT EXISTS may do nothing, but it is still not a failure. don't forget to my_ok it. sql/sql_table.cc: small cleanup ****** small cleanup
2011-10-19 21:45:18 +02:00
table_list->reset_const_table();
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
table->null_row= 0;
table->status= STATUS_NO_RECORD;
table->maybe_null= table_list->outer_join;
TABLE_LIST *embedding= table_list->embedding;
while (!table->maybe_null && embedding)
{
table->maybe_null= embedding->outer_join;
embedding= embedding->embedding;
}
table->tablenr= tablenr;
table->map= (table_map) 1 << tablenr;
table->force_index= table_list->force_index;
table->force_index_order= table->force_index_group= 0;
table->covering_keys= table->s->keys_for_keyread;
}
inline TABLE_LIST *find_table_in_global_list(TABLE_LIST *table,
Changed database, tablename and alias to be LEX_CSTRING This was done in, among other things: - thd->db and thd->db_length - TABLE_LIST tablename, db, alias and schema_name - Audit plugin database name - lex->db - All db and table names in Alter_table_ctx - st_select_lex db Other things: - Changed a lot of functions to take const LEX_CSTRING* as argument for db, table_name and alias. See init_one_table() as an example. - Changed some function arguments from LEX_CSTRING to const LEX_CSTRING - Changed some lists from LEX_STRING to LEX_CSTRING - threads_mysql.result changed because process list_db wasn't always correctly updated - New append_identifier() function that takes LEX_CSTRING* as arguments - Added new element tmp_buff to Alter_table_ctx to separate temp name handling from temporary space - Ensure we store the length after my_casedn_str() of table/db names - Removed not used version of rename_table_in_stat_tables() - Changed Natural_join_column::table_name and db_name() to never return NULL (used for print) - thd->get_db() now returns db as a printable string (thd->db.str or "")
2018-01-07 17:03:44 +01:00
LEX_CSTRING *db_name,
LEX_CSTRING *table_name)
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
{
return find_table_in_list(table, &TABLE_LIST::next_global,
db_name, table_name);
}
This is the consolidated patch for mdev-8646: "Re-factor the code for post-join operations". The patch mainly contains the code ported from mysql-5.6 and created for two essential architectural changes: 1. WL#5558: Resolve ORDER BY execution method at the optimization stage 2. WL#6071: Inline tmp tables into the nested loops algorithm The first task was implemented for mysql-5.6 by Ole John Aske. It allows to make all decisions on ORDER BY operation at the optimization stage. The second task implemented for mysql-5.6 by Evgeny Potemkin adds JOIN_TAB nodes for post-join operations that require temporary tables. It allows to execute these operations within the nested loops algorithm that used to be used before this task only for join queries. Besides these task moves all planning on the execution of these operations from the execution phase to the optimization phase. Some other re-factoring changes of mysql-5.6 were pulled in, mainly because it was easier to pull them in than roll them back. In particular all changes concerning Ref_ptr_array were incorporated. The port required some changes in the MariaDB code that concerned the functionality of EXPLAIN and ANALYZE. This was done mainly by Sergey Petrunia.
2016-02-09 21:35:59 +01:00
inline bool setup_fields_with_no_wrap(THD *thd, Ref_ptr_array ref_pointer_array,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
List<Item> &item,
cleanup: renames enum_mark_columns -> enum_column_usage mark_used_columns -> column_usage further commits will replace MARK_COLUMN_NONE with COLUMN_READ and COLUMN_WRITE that convey the intention without causing columns to be marked
2018-02-09 19:43:42 +01:00
enum_column_usage column_usage,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
List<Item> *sum_func_list,
bool allow_sum_func)
{
bool res;
MDEV-11953: support of brackets in UNION/EXCEPT/INTERSECT operations
2018-05-22 19:08:39 +02:00
SELECT_LEX *first= thd->lex->first_select_lex();
DBUG_ASSERT(thd->lex->current_select == first);
first->no_wrap_view_item= TRUE;
cleanup: renames enum_mark_columns -> enum_column_usage mark_used_columns -> column_usage further commits will replace MARK_COLUMN_NONE with COLUMN_READ and COLUMN_WRITE that convey the intention without causing columns to be marked
2018-02-09 19:43:42 +01:00
res= setup_fields(thd, ref_pointer_array, item, column_usage,
MDEV-9619: Assertion `null_ref_table' failed in virtual table_map Item_direct_view_ref::used_tables() const on 2nd execution of PS Refer left expression indirectly in case it changes from execution to execution.
2017-02-18 17:47:31 +01:00
sum_func_list, NULL, allow_sum_func);
MDEV-11953: support of brackets in UNION/EXCEPT/INTERSECT operations
2018-05-22 19:08:39 +02:00
first->no_wrap_view_item= FALSE;
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
return res;
}
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
/**
An abstract class for a strategy specifying how the prelocking
algorithm should extend the prelocking set while processing
already existing elements in the set.
*/
class Prelocking_strategy
{
public:
Apply clang-tidy to remove empty constructors / destructors This patch is the result of running run-clang-tidy -fix -header-filter=.* -checks='-*,modernize-use-equals-default' . Code style changes have been done on top. The result of this change leads to the following improvements: 1. Binary size reduction. * For a -DBUILD_CONFIG=mysql_release build, the binary size is reduced by ~400kb. * A raw -DCMAKE_BUILD_TYPE=Release reduces the binary size by ~1.4kb. 2. Compiler can better understand the intent of the code, thus it leads to more optimization possibilities. Additionally it enabled detecting unused variables that had an empty default constructor but not marked so explicitly. Particular change required following this patch in sql/opt_range.cc result_keys, an unused template class Bitmap now correctly issues unused variable warnings. Setting Bitmap template class constructor to default allows the compiler to identify that there are no side-effects when instantiating the class. Previously the compiler could not issue the warning as it assumed Bitmap class (being a template) would not be performing a NO-OP for its default constructor. This prevented the "unused variable warning".
2023-02-07 12:57:20 +01:00
virtual ~Prelocking_strategy() = default;
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
MDEV-19491 update query stopped working after mariadb upgrade 10.2.23 -> 10.2.24 as well as MDEV-19500 Update with join stopped worked if there is a call to a procedure in a trigger MDEV-19521 Update Table Fails with Trigger and Stored Function MDEV-19497 Replication stops because table not found MDEV-19527 UPDATE + JOIN + TRIGGERS = table doesn't exists error Reimplement the fix for (5d510fdbf00) MDEV-18507 can't update temporary table when joined with table with triggers on read-only instead of calling open_tables() twice, put multi-update prepare code inside open_tables() loop. Add a test for a MDL backoff-and-retry loop inside open_tables() across multi-update prepare code.
2019-05-22 21:56:36 +02:00
virtual void reset(THD *thd) { };
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
virtual bool handle_routine(THD *thd, Query_tables_list *prelocking_ctx,
Sroutine_hash_entry *rt, sp_head *sp,
bool *need_prelocking) = 0;
virtual bool handle_table(THD *thd, Query_tables_list *prelocking_ctx,
TABLE_LIST *table_list, bool *need_prelocking) = 0;
virtual bool handle_view(THD *thd, Query_tables_list *prelocking_ctx,
TABLE_LIST *table_list, bool *need_prelocking)= 0;
MDEV-19491 update query stopped working after mariadb upgrade 10.2.23 -> 10.2.24 as well as MDEV-19500 Update with join stopped worked if there is a call to a procedure in a trigger MDEV-19521 Update Table Fails with Trigger and Stored Function MDEV-19497 Replication stops because table not found MDEV-19527 UPDATE + JOIN + TRIGGERS = table doesn't exists error Reimplement the fix for (5d510fdbf00) MDEV-18507 can't update temporary table when joined with table with triggers on read-only instead of calling open_tables() twice, put multi-update prepare code inside open_tables() loop. Add a test for a MDL backoff-and-retry loop inside open_tables() across multi-update prepare code.
2019-05-22 21:56:36 +02:00
virtual bool handle_end(THD *thd) { return 0; };
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
};
/**
A Strategy for prelocking algorithm suitable for DML statements.
Ensures that all tables used by all statement's SF/SP/triggers and
required for foreign key checks are prelocked and SF/SPs used are
cached.
*/
class DML_prelocking_strategy : public Prelocking_strategy
{
public:
virtual bool handle_routine(THD *thd, Query_tables_list *prelocking_ctx,
Sroutine_hash_entry *rt, sp_head *sp,
bool *need_prelocking);
virtual bool handle_table(THD *thd, Query_tables_list *prelocking_ctx,
TABLE_LIST *table_list, bool *need_prelocking);
virtual bool handle_view(THD *thd, Query_tables_list *prelocking_ctx,
TABLE_LIST *table_list, bool *need_prelocking);
};
/**
A strategy for prelocking algorithm to be used for LOCK TABLES
statement.
*/
class Lock_tables_prelocking_strategy : public DML_prelocking_strategy
{
virtual bool handle_table(THD *thd, Query_tables_list *prelocking_ctx,
TABLE_LIST *table_list, bool *need_prelocking);
};
/**
Strategy for prelocking algorithm to be used for ALTER TABLE statements.
Unlike DML or LOCK TABLES strategy, it doesn't
prelock triggers, views or stored routines, since they are not
used during ALTER.
*/
class Alter_table_prelocking_strategy : public Prelocking_strategy
{
public:
virtual bool handle_routine(THD *thd, Query_tables_list *prelocking_ctx,
Sroutine_hash_entry *rt, sp_head *sp,
bool *need_prelocking);
virtual bool handle_table(THD *thd, Query_tables_list *prelocking_ctx,
TABLE_LIST *table_list, bool *need_prelocking);
virtual bool handle_view(THD *thd, Query_tables_list *prelocking_ctx,
TABLE_LIST *table_list, bool *need_prelocking);
};
MDEV-7112 Split HA_CREATE_INFO
2014-12-08 07:56:08 +01:00
inline bool
open_tables(THD *thd, const DDL_options_st &options,
TABLE_LIST **tables, uint *counter, uint flags)
{
DML_prelocking_strategy prelocking_strategy;
return open_tables(thd, options, tables, counter, flags,
&prelocking_strategy);
}
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
inline bool
open_tables(THD *thd, TABLE_LIST **tables, uint *counter, uint flags)
{
DML_prelocking_strategy prelocking_strategy;
MDEV-7112 Split HA_CREATE_INFO
2014-12-08 07:56:08 +01:00
return open_tables(thd, thd->lex->create_info, tables, counter, flags,
&prelocking_strategy);
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
}
Fix for bug #56251 "Deadlock with INSERT DELAYED and MERGE tables". Attempting to issue an INSERT DELAYED statement for a MERGE table might have caused a deadlock if it happened as part of a transaction or under LOCK TABLES, and there was a concurrent DDL or LOCK TABLES ... WRITE statement which tried to lock one of its underlying tables. The problem occurred when a delayed insert handler thread tried to open a MERGE table and discovered that to do this it had also to open all underlying tables and hence acquire metadata locks on them. Since metadata locks on the underlying tables were not pre-acquired by the connection thread executing INSERT DELAYED, attempts to do so might lead to waiting. In this case the connection thread had to wait for the delayed insert thread. If the thread which was preventing the lock on the underlying table from being acquired had to wait for the connection thread (due to this or other metadata locks), a deadlock occurred. This deadlock was not detected by the MDL deadlock detector since waiting for the handler thread by the connection thread is not represented in the wait-for graph. This patch solves the problem by ensuring that the delayed insert handler thread never tries to open underlying tables of a MERGE table. Instead open_tables() is aborted right after the parent table is opened and a ER_DELAYED_NOT_SUPPORTED error is emitted (which is passed to the connection thread and ultimately to the user). mysql-test/r/merge.result: Added test for bug #56251 "Deadlock with INSERT DELAYED and MERGE tables". mysql-test/t/merge.test: Added test for bug #56251 "Deadlock with INSERT DELAYED and MERGE tables". sql/sql_base.cc: Changed open_n_lock_single_table() to take prelocking strategy as an argument instead of always using DML_prelocking_strategy. sql/sql_base.h: Changed open_n_lock_single_table() to take prelocking strategy as an argument instead of always using DML_prelocking_strategy. Added a version of this function which is compatible with old signature. sql/sql_insert.cc: When opening MERGE table in delayed insert thread stop and emit ER_DELAYED_NOT_SUPPORTED right after opening main table and before opening underlying tables. This ensures that we won't try to acquire metadata lock on underlying tables which might lead to a deadlock. This is achieved by using special prelocking strategy which abort open_tables() process as soon as we discover that we have opened table with engine which doesn't support delayed inserts.
2010-09-15 16:15:31 +02:00
inline TABLE *open_n_lock_single_table(THD *thd, TABLE_LIST *table_l,
thr_lock_type lock_type, uint flags)
{
DML_prelocking_strategy prelocking_strategy;
return open_n_lock_single_table(thd, table_l, lock_type, flags,
&prelocking_strategy);
}
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
/* open_and_lock_tables with derived handling */
MDEV-7112 Split HA_CREATE_INFO
2014-12-08 07:56:08 +01:00
inline bool open_and_lock_tables(THD *thd,
const DDL_options_st &options,
TABLE_LIST *tables,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
bool derived, uint flags)
{
DML_prelocking_strategy prelocking_strategy;
MDEV-7112 Split HA_CREATE_INFO
2014-12-08 07:56:08 +01:00
return open_and_lock_tables(thd, options, tables, derived, flags,
&prelocking_strategy);
}
inline bool open_and_lock_tables(THD *thd, TABLE_LIST *tables,
bool derived, uint flags)
{
DML_prelocking_strategy prelocking_strategy;
return open_and_lock_tables(thd, thd->lex->create_info,
tables, derived, flags,
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
&prelocking_strategy);
}
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
Implementation of MDEV-5491: CREATE OR REPLACE TABLE Using CREATE OR REPLACE TABLE is be identical to DROP TABLE IF EXISTS table_name; CREATE TABLE ...; Except that: * CREATE OR REPLACE is be atomic (now one can create the same table between drop and create). * Temporary tables will not shadow the table name for the DROP as the CREATE TABLE tells us already if we are using a temporary table or not. * If the table was locked with LOCK TABLES, the new table will be locked with the same lock after it's created. Implementation details: - We don't anymore open the to-be-created table during CREATE TABLE, which the original code did. - There is no need to open a table we are planning to create. It's enough to check if the table exists or not. - Removed some of duplicated code for CREATE IF NOT EXISTS. - Give an error when using CREATE OR REPLACE with IF NOT EXISTS (conflicting options). - As a side effect of the code changes, we don't anymore have to internally re-prepare prepared statements with CREATE TABLE if the table exists. - Made one code path for all testing if log table are in use. - Better error message if one tries to create/drop/alter a log table in use - Added back disabled rpl_row_create_table test as it now seams to work and includes a lot of interesting tests. - Added HA_LEX_CREATE_REPLACE to mark if we are using CREATE OR REPLACE - Aligned CREATE OR REPLACE parsing code in sql_yacc.yy for TABLE and VIEW - Changed interface for drop_temporary_table() to make it more reusable - Changed Locked_tables_list::init_locked_tables() to work on the table object instead of the table list object. Before this it used a mix of both, which was not good. - Locked_tables_list::unlock_locked_tables(THD *thd) now requires a valid thd argument. Old usage of calling this with 0 i changed to instead call Locked_tables_list::reset() - Added functions Locked_tables_list:restore_lock() and Locked_tables_list::add_back_last_deleted_lock() to be able to easily add back a locked table to the lock list. - Added restart_trans_for_tables() to be able to restart a transaction. - DROP_ACL is required if one uses CREATE TABLE OR REPLACE. - Added drop of normal and temporary tables in create_table_imp() if CREATE OR REPLACE was used. - Added reacquiring of table locks in mysql_create_table() and mysql_create_like_table() mysql-test/include/commit.inc: With new code we get fewer status increments mysql-test/r/commit_1innodb.result: With new code we get fewer status increments mysql-test/r/create.result: Added testing of create or replace with timeout mysql-test/r/create_or_replace.result: Basic testing of CREATE OR REPLACE TABLE mysql-test/r/partition_exchange.result: New error message mysql-test/r/ps_ddl.result: Fewer reprepares with new code mysql-test/suite/archive/discover.result: Don't rediscover archive tables if the .frm file exists (Sergei will look at this if there is a better way...) mysql-test/suite/archive/discover.test: Don't rediscover archive tables if the .frm file exists (Sergei will look at this if there is a better way...) mysql-test/suite/funcs_1/r/innodb_views.result: New error message mysql-test/suite/funcs_1/r/memory_views.result: New error message mysql-test/suite/rpl/disabled.def: rpl_row_create_table should now be safe to use mysql-test/suite/rpl/r/rpl_row_create_table.result: Updated results after adding back disabled test mysql-test/suite/rpl/t/rpl_create_if_not_exists.test: Added comment mysql-test/suite/rpl/t/rpl_row_create_table.test: Added CREATE OR REPLACE TABLE test mysql-test/t/create.test: Added CREATE OR REPLACE TABLE test mysql-test/t/create_or_replace-master.opt: Create logs mysql-test/t/create_or_replace.test: Basic testing of CREATE OR REPLACE TABLE mysql-test/t/partition_exchange.test: Error number changed as we are now using same code for all log table change issues mysql-test/t/ps_ddl.test: Fewer reprepares with new code sql/handler.h: Moved things around a bit in a structure to get better alignment. Added HA_LEX_CREATE_REPLACE to mark if we are using CREATE OR REPLACE Added 3 elements to end of HA_CREATE_INFO to be able to store state to add backs locks in case of LOCK TABLES. sql/log.cc: Reimplemented check_if_log_table(): - Simpler and faster usage - Can give error messages This gives us one code path for allmost all error messages if log tables are in use sql/log.h: New interface for check_if_log_table() sql/slave.cc: More logging sql/sql_alter.cc: New interface for check_if_log_table() sql/sql_base.cc: More documentation Changed interface for drop_temporary_table() to make it more reusable Changed Locked_tables_list::init_locked_tables() to work on the table object instead of the table list object. Before this it used a mix of both, which was not good. Locked_tables_list::unlock_locked_tables(THD *thd) now requires a valid thd argument. Old usage of calling this with 0 i changed to instead call Locked_tables_list::reset() Added functions Locked_tables_list:restore_lock() and Locked_tables_list::add_back_last_deleted_lock() to be able to easily add back a locked table to the lock list. Check for command number instead of open_strategy of CREATE TABLE was used. Added restart_trans_for_tables() to be able to restart a transaction. This was needed in "create or replace ... select" between the drop table and the select. sql/sql_base.h: Added and updated function prototypes sql/sql_class.h: Added new prototypes to Locked_tables_list class Added extra argument to select_create to avoid double call to eof() or send_error() - I needed this in some edge case where the table was not created against expections. sql/sql_db.cc: New interface for check_if_log_table() sql/sql_insert.cc: Remember position to lock information so that we can reaquire table lock for LOCK TABLES + CREATE OR REPLACE TABLE SELECT. Later add back the lock by calling restore_lock(). Removed one not needed indentation level in create_table_from_items() Ensure we don't call send_eof() or abort_result_set() twice. sql/sql_lex.h: Removed variable that I temporarly added in an earlier changeset sql/sql_parse.cc: Removed old test code (marked with QQ) Ensure that we have open_strategy set as TABLE_LIST::OPEN_STUB in CREATE TABLE Removed some IF NOT EXISTS code as this is now handled in create_table_table_impl(). Set OPTION_KEEP_LOGS later. This code had to be moved as the test for IF EXISTS has changed place. DROP_ACL is required if one uses CREATE TABLE OR REPLACE. sql/sql_partition_admin.cc: New interface for check_if_log_table() sql/sql_rename.cc: New interface for check_if_log_table() sql/sql_table.cc: New interface for check_if_log_table() Moved some code in mysql_rm_table() under a common test. - Safe as temporary tables doesn't have statistics. - !is_temporary_table(table) test was moved out from drop_temporary_table() and merged with upper level code. - Added drop of normal and temporary tables in create_table_imp() if CREATE OR REPLACE was used. - Added reacquiring of table locks in mysql_create_table() and mysql_create_like_table() - In mysql_create_like_table(), restore table->open_strategy() if it was changed. - Re-test if table was a view after opening it. sql/sql_table.h: New prototype for mysql_create_table_no_lock() sql/sql_yacc.yy: Added syntax for CREATE OR REPLACE TABLE Reuse new code for CREATE OR REPLACE VIEW sql/table.h: Added name for enum type sql/table_cache.cc: More DBUG
2014-01-29 14:37:17 +01:00
bool restart_trans_for_tables(THD *thd, TABLE_LIST *table);
cleanup
2019-04-03 17:21:10 +02:00
bool extend_table_list(THD *thd, TABLE_LIST *tables,
Prelocking_strategy *prelocking_strategy,
bool has_prelocking_list);
MDEV-25576: The statement EXPLAIN running as regular statement and as prepared statement produces different results for UPDATE with subquery Both EXPLAIN and EXPLAIN EXTENDED statements produce different results set in case it is run in normal way and in PS mode for the statements UPDATE/DELETE with subquery. The use case below reproduces the issue: MariaDB [test]> CREATE TABLE t1 (c1 INT KEY) ENGINE=MyISAM; Query OK, 0 rows affected (0,128 sec) MariaDB [test]> CREATE TABLE t2 (c2 INT) ENGINE=MyISAM; Query OK, 0 rows affected (0,023 sec) MariaDB [test]> CREATE TABLE t3 (c3 INT) ENGINE=MyISAM; Query OK, 0 rows affected (0,021 sec) MariaDB [test]> EXPLAIN EXTENDED UPDATE t3 SET c3 = -> ( SELECT COUNT(d1.c1) FROM ( SELECT a11.c1 FROM t1 AS a11 -> STRAIGHT_JOIN t2 AS a21 ON a21.c2 = a11.c1 JOIN t1 AS a12 -> ON a12.c1 = a11.c1 ) d1 ); +------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra | +------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+ | 1 | PRIMARY | t3 | ALL | NULL | NULL | NULL | NULL | 0 | 100.00 | | | 2 | SUBQUERY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Impossible WHERE noticed after reading const tables +------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+ 2 rows in set (0,002 sec) MariaDB [test]> PREPARE stmt FROM -> EXPLAIN EXTENDED UPDATE t3 SET c3 = -> ( SELECT COUNT(d1.c1) FROM ( SELECT a11.c1 FROM t1 AS a11 -> STRAIGHT_JOIN t2 AS a21 ON a21.c2 = a11.c1 JOIN t1 AS a12 -> ON a12.c1 = a11.c1 ) d1 ); Query OK, 0 rows affected (0,000 sec) Statement prepared MariaDB [test]> EXECUTE stmt; +------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra | +------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+ | 1 | PRIMARY | t3 | ALL | NULL | NULL | NULL | NULL | 0 | 100.00 | | | 2 | SUBQUERY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | no matching row in const table | +------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+ 2 rows in set (0,000 sec) The reason by that different result sets are produced is that on execution of the statement 'EXECUTE stmt' the flag SELECT_DESCRIBE not set in the data member SELECT_LEX::options for instances of SELECT_LEX that correspond to subqueries used in the UPDTAE/DELETE statements. Initially, these flags were set on parsing the statement PREPARE stmt FROM "EXPLAIN EXTENDED UPDATE t3 SET ..." but latter they were reset before starting real execution of the parsed query during handling the statement 'EXECUTE stmt'; So, to fix the issue the functions mysql_update()/mysql_delete() have been modified to set the flag SELECT_DESCRIBE forcibly in the data member SELECT_LEX::options for the primary SELECT_LEX of the UPDATE/DELETE statement.
2021-05-30 12:31:55 +02:00
void promote_select_describe_flag_if_needed(LEX *lex);
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
/**
A context of open_tables() function, used to recover
from a failed open_table() or open_routine() attempt.
*/
class Open_table_context
{
public:
enum enum_open_table_action
{
OT_NO_ACTION= 0,
Commit on behalf of Dmitry Lenev. Merge his patch for Bug#52044 into 5.5, and apply review comments.
2010-08-12 15:50:23 +02:00
OT_BACKOFF_AND_RETRY,
Fix for bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". The problem was that FLUSH TABLES <list> WITH READ LOCK which was issued when other connection has acquired global read lock using FLUSH TABLES WITH READ LOCK was blocked and has to wait until global read lock is released. This issue stemmed from the fact that FLUSH TABLES <list> WITH READ LOCK implementation has acquired X metadata locks on tables to be flushed. Since these locks required acquiring of global IX lock this statement was incompatible with global read lock. This patch addresses problem by using SNW metadata type of lock for tables to be flushed by FLUSH TABLES <list> WITH READ LOCK. It is OK to acquire them without global IX lock as long as we won't try to upgrade those locks. Since SNW locks allow concurrent statements using same table FLUSH TABLE <list> WITH READ LOCK now has to wait until old versions of tables to be flushed go away after acquiring metadata locks. Since such waiting can lead to deadlock MDL deadlock detector was extended to take into account waits for flush and resolve such deadlocks. As a bonus code in open_tables() which was responsible for waiting old versions of tables to go away was refactored. Now when we encounter old version of table in open_table() we don't back-off and wait for all old version to go away, but instead wait for this particular table to be flushed. Such approach supported by deadlock detection should reduce number of scenarios in which FLUSH TABLES aborts concurrent multi-statement transactions. Note that active FLUSH TABLES <list> WITH READ LOCK still blocks concurrent FLUSH TABLES WITH READ LOCK statement as the former keeps tables open and thus prevents the latter statement from doing flush. mysql-test/include/handler.inc: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/r/flush.result: Added test which checks that "flush tables <list> with read lock" is compatible with active "flush tables with read lock" but not vice-versa. This test also covers bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". mysql-test/r/mdl_sync.result: Added scenarios in which wait for table to be flushed causes deadlocks to the coverage of MDL deadlock detector. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Adjusted test results after removal of COND_refresh condition variable. mysql-test/suite/perfschema/r/server_init.result: Adjusted test and its results after removal of COND_refresh condition variable. mysql-test/suite/perfschema/t/server_init.test: Adjusted test and its results after removal of COND_refresh condition variable. mysql-test/t/flush.test: Added test which checks that "flush tables <list> with read lock" is compatible with active "flush tables with read lock" but not vice-versa. This test also covers bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". mysql-test/t/kill.test: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/t/lock_multi.test: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/t/mdl_sync.test: Added scenarios in which wait for table to be flushed causes deadlocks to the coverage of MDL deadlock detector. sql/ha_ndbcluster.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/ha_ndbcluster_binlog.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/lock.cc: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/mdl.cc: Now MDL deadlock detector takes into account information about waits for table flushes when searching for deadlock. To implement this change: - Declaration of enum_deadlock_weight and Deadlock_detection_visitor were moved to mdl.h header to make them available to the code in table.cc which implements deadlock detector traversal through edges of waiters graph representing waiting for flush. - Since now MDL_context may wait not only for metadata lock but also for table to be flushed an abstract Wait_for_edge class was introduced. Its descendants MDL_ticket and Flush_ticket incapsulate specifics of inspecting waiters graph when following through edge representing wait of particular type. We no longer require global IX metadata lock when acquiring SNW or SNRW locks. Such locks are needed only when metadata locks of these types are upgraded to X locks. This allows to use SNW locks in FLUSH TABLES <list> WITH READ LOCK implementation and keep the latter compatible with global read lock. sql/mdl.h: Now MDL deadlock detector takes into account information about waits for table flushes when searching for deadlock. To implement this change: - Declaration of enum_deadlock_weight and Deadlock_detection_visitor were moved to mdl.h header to make them available to the code in table.cc which implements deadlock detector traversal through edges of waiters graph representing waiting for flush. - Since now MDL_context may wait not only for metadata lock but also for table to be flushed an abstract Wait_for_edge class was introduced. Its descendants MDL_ticket and Flush_ticket incapsulate specifics of inspecting waiters graph when following through edge representing wait of particular type. - Deadlock_detection_visitor now has m_table_shares_visited member which allows to support recursive locking for LOCK_open. This is required when deadlock detector inspects waiters graph which contains several edges representing waits for flushes or needs to come through the such edge more than once. sql/mysqld.cc: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/mysqld.h: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/sql_base.cc: Changed approach to how threads are waiting for table to be flushed. Now thread that wants to wait for old table to go away subscribes for notification by adding Flush_ticket to table's share and waits using MDL_context::m_wait object. Once table gets flushed (i.e. all tables are closed and table share is ready to be destroyed) all such waiters are notified individually. Thanks to this change MDL deadlock detector can take such waits into account. To implement this/as result of this change: - tdc_wait_for_old_versions() was replaced with tdc_wait_for_old_version() which waits for individual old share to go away and which is called by open_table() after finding out that share is outdated. We don't need to perform back-off before such waiting thanks to the fact that deadlock detector now sees such waits. - As result Open_table_ctx::m_mdl_requests became unnecessary and was removed. We no longer allocate copies of MDL_request objects on MEM_ROOT when MYSQL_OPEN_FORCE_SHARED/SHARED_HIGH_PRIO flags are in effect. - close_cached_tables() and tdc_wait_for_old_version() share code which implements waiting for share to be flushed - the both use TABLE_SHARE::wait_until_flush() method. Thanks to this close_cached_tables() supports timeouts and has extra parameter for this. - Open_table_context::OT_MDL_CONFLICT enum element was renamed to OT_CONFLICT as it is now also used in cases when back-off is required to resolve deadlock caused by waiting for flush and not metadata lock. - In cases when we discover that current connection tries to open tables from different generation we now simply back-off and restart process of opening tables. To support this Open_table_context::OT_REOPEN_TABLES enum element was added. - COND_refresh condition variable became unnecessary and was removed. - mysql_notify_thread_having_shared_lock() no longer wakes up connections waiting for flush as all such connections can be waken up by deadlock detector if necessary. sql/sql_base.h: - close_cached_tables() now has one more parameter - timeout for waiting for table to be flushed. - Open_table_context::OT_MDL_CONFLICT enum element was renamed to OT_CONFLICT as it is now also used in cases when back-off is required to resolve deadlock caused by waiting for flush and not metadata lock. Added new OT_REOPEN_TABLES enum element to be used in cases when we need to restart open tables process even in the middle of transaction. - Open_table_ctx::m_mdl_requests became unnecessary and was removed. sql/sql_class.h: Added assert ensuring that we won't use LOCK_open mutex with THD::enter_cond(). Otherwise deadlocks can arise in MDL deadlock detector. sql/sql_parse.cc: Changed FLUSH TABLES <list> WITH READ LOCK to take SNW metadata locks instead of X locks on tables to be flushed. Since we no longer require global IX lock to be taken when SNW locks are taken this makes this statement compatible with FLUSH TABLES WITH READ LOCK statement. Since SNW locks allow other connections to have table opened FLUSH TABLES <list> WITH READ LOCK now has to wait during open_tables() for old version to go away. Such waits can lead to deadlocks which will be detected by MDL deadlock detector which now takes waits for table to be flushed into account. Also adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/sql_yacc.yy: FLUSH TABLES <list> WITH READ LOCK now needs only SNW metadata locks on tables. sql/sys_vars.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/table.cc: Implemented new approach to how threads are waiting for table to be flushed. Now thread that wants to wait for old table to go away subscribes for notification by adding Flush_ticket to table's share and waits using MDL_context::m_wait object. Once table gets flushed (i.e. all tables are closed and table share is ready to be destroyed) all such waiters are notified individually. This change allows to make such waits visible inside of MDL deadlock detector. To do it: - Added list of waiters/Flush_tickets to TABLE_SHARE class. - Changed free_table_share() to postpone freeing of share memory until last waiter goes away and to wake up subscribed waiters. - Added TABLE_SHARE::wait_until_flushed() method which implements subscription to the list of waiters for table to be flushed and waiting for this event. Implemented interface which allows to expose waits for flushes to MDL deadlock detector: - Introduced Flush_ticket class a descendant of Wait_for_edge class. - Added TABLE_SHARE::find_deadlock() method which allows deadlock detector to find out what contexts are still using old version of table in question (i.e. to find out what contexts are waited for by owner of Flush_ticket). sql/table.h: In order to support new strategy of waiting for table flush (see comment for table.cc for details) added list of waiters/Flush_tickets to TABLE_SHARE class. Implemented interface which allows to expose waits for flushes to MDL deadlock detector: - Introduced Flush_ticket class a descendant of Wait_for_edge class. - Added TABLE_SHARE::find_deadlock() method which allows deadlock detector to find out what contexts are still using old version of table in question (i.e. to find out what contexts are waited for by owner of Flush_ticket).
2010-07-27 15:34:58 +02:00
OT_REOPEN_TABLES,
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
OT_DISCOVER,
OT_REPAIR
};
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Make open flags part of Open_table_context. This allows to simplify some code and (in future) enforce the invariant that we don't, say, request a back off on the table when there is MYSQL_OPEN_IGNORE_FLUSH flag. sql/sql_base.cc: open_table() flags are part of Open_table_context. Remove dead code that would check for OPEN_VIEW_NO_PARSE, which is not an open table flag. sql/sql_base.h: Move flags to Open_table_context. Reorder Open_table_context members to compact the structure footprint. sql/sql_insert.cc: Update with a new calling signature of open_table(). sql/sql_table.cc: Update with a new calling signature of open_table().
2010-06-01 12:49:35 +02:00
Open_table_context(THD *thd, uint flags);
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
Fix for bug#14188793 - "DEADLOCK CAUSED BY ALTER TABLE DOEN'T CLEAR STATUS OF ROLLBACKED TRANSACTION" and bug #17054007 - "TRANSACTION IS NOT FULLY ROLLED BACK IN CASE OF INNODB DEADLOCK". The problem in the first bug report was that although deadlock involving metadata locks was reported using the same error code and message as InnoDB deadlock it didn't rollback transaction like the latter. This caused confusion to users as in some cases after ER_LOCK_DEADLOCK transaction could have been restarted immediately and in some cases rollback was required. The problem in the second bug report was that although InnoDB deadlock caused transaction rollback in all storage engines it didn't cause release of metadata locks. So concurrent DDL on the tables used in transaction was blocked until implicit or explicit COMMIT or ROLLBACK was issued in the connection which got InnoDB deadlock. The former issue has stemmed from the fact that when support for detection and reporting metadata locks deadlocks was added we erroneously assumed that InnoDB doesn't rollback transaction on deadlock but only last statement (while this is what happens on InnoDB lock timeout actually) and so didn't implement rollback of transactions on MDL deadlocks. The latter issue was caused by the fact that rollback of transaction due to deadlock is carried out by setting THD::transaction_rollback_request flag at the point where deadlock is detected and performing rollback inside of trans_rollback_stmt() call when this flag is set. And trans_rollback_stmt() is not aware of MDL locks, so no MDL locks are released. This patch solves these two problems in the following way: - In case when MDL deadlock is detect transaction rollback is requested by setting THD::transaction_rollback_request flag. - Code performing rollback of transaction if THD::transaction_rollback_request is moved out from trans_rollback_stmt(). Now we handle rollback request on the same level as we call trans_rollback_stmt() and release statement/ transaction MDL locks.
2013-08-20 11:12:34 +02:00
bool recover_from_failed_open();
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
bool request_backoff_action(enum_open_table_action action_arg,
Patch that changes approach to how we acquire metadata locks for DML statements and changes the way MDL locks are acquired/granted in contended case. Instead of backing-off when a lock conflict is encountered and waiting for it to go away before restarting open_tables() process we now wait for lock to be released without releasing any previously acquired locks. If conflicting lock goes away we resume opening tables. If waiting leads to a deadlock we try to resolve it by backing-off and restarting open_tables() immediately. As result both waiting for possibility to acquire and acquiring of a metadata lock now always happen within the same MDL API call. This has allowed to make release of a lock and granting it to the most appropriate pending request an atomic operation. Thanks to this it became possible to wake up during release of lock only those waiters which requests can be satisfied at the moment as well as wake up only one waiter in case when granting its request would prevent all other requests from being satisfied. This solves thundering herd problem which occured in cases when we were releasing some lock and woke up many waiters for SNRW or X locks (this was the issue in bug#52289 "performance regression for MyISAM in sysbench OLTP_RW test". This also allowed to implement more fair (FIFO) scheduling among waiters with the same priority. It also opens the door for introducing new types of requests for metadata locks such as low-prio SNRW lock which is necessary in order to support LOCK TABLES LOW_PRIORITY WRITE. Notice that after this sometimes can report ER_LOCK_DEADLOCK error in cases in which it has not happened before. Particularly we will always report this error if waiting for conflicting lock has happened in the middle of transaction and resulted in a deadlock. Before this patch the error was not reported if deadlock could have been resolved by backing off all metadata locks acquired by the current statement. mysql-test/r/mdl_sync.result: Added test coverage for some aspects of deadlock handling in metadata locking subsystem. Adjusted test case after removing back-off in general case when conflicting metadata lock is encountered during open_tables() (now this happens only if waiting for conflicting lock to go away leads to a deadlock). mysql-test/r/sp_sync.result: Adjusted test case after removing back-off in general case when conflicting metadata lock is encountered during open_tables() (now this happens only if waiting for conflicting lock to go away leads to a deadlock). mysql-test/suite/perfschema/r/dml_setup_instruments.result: Adjusted test results after renaming MDL_context:: m_waiting_for_lock rwlock to m_LOCK_waiting_for. mysql-test/suite/rpl/r/rpl_sp.result: Adjusted test case after implementing new approach to acquiring metadata locks in open_tables(). We no longer release all MDL locks acquired by statement before waiting for conflicting lock to go away. As result DROP FUNCTION statement has to wait for DML statement which managed to acquire metadata lock on function being dropped and now waits for other conflicting metadata lock to go away. mysql-test/suite/rpl/t/rpl_sp.test: Adjusted test case after implementing new approach to acquiring metadata locks in open_tables(). We no longer release all MDL locks acquired by statement before waiting for conflicting lock to go away. As result DROP FUNCTION statement has to wait for DML statement which managed to acquire metadata lock on function being dropped and now waits for other conflicting metadata lock to go away. mysql-test/t/mdl_sync.test: Added test coverage for some aspects of deadlock handling in metadata locking subsystem. Adjusted test case after removing back-off in general case when conflicting metadata lock is encountered during open_tables() (now this happens only if waiting for conflicting lock to go away leads to a deadlock). mysql-test/t/sp_sync.test: Adjusted test case after removing back-off in general case when conflicting metadata lock is encountered during open_tables() (now this happens only if waiting for conflicting lock to go away leads to a deadlock). sql/mdl.cc: Changed MDL subsystem to support new approach to acquring metadata locks in open tables and more fair and efficient scheduling of metadata locks. To implement this: - Made releasing of the lock and granting it to the most appropriate pending request atomic operation. As result it became possible to wake up only those waiters requests from which can be satisfied at the moment as well as wake-up only one waiter in case when granting its request would prevent all other requests from being satisfied. This solved thundering herd problem which occured in cases when we were releasing some lock and woke up many waiters for SNRW or X locks (this was the issue in Bug #52289 "performance regression for MyISAM in sysbench OLTP_RW test". To emphasize above changes wake_up_waiters() was renamed to MDL_context::reschedule_waiters(). - Changed code to add tickets for new requests to the back of waiters queue and to select tickets to be satisfied from the head of the queue if possible (this makes scheduling of requests with the same priority fair). To be able to do this efficiently we now use for waiting and granted queues version of I_P_List class which provides fast push_back() method. - Members and methods of MDL_context related to sending and waiting for signal were moved to separate MDL_wait class. - Since in order to avoid race conditions we must grant the lock only to the context which was not chosen as a victim of deadlock, killed or aborted due to timeout MDL_wait::set_status() (former awake()) was changed not to send signal if signal slot is already occupied and to indicate this fact through its return value. As another consequence MDL_wait::timed_wait() method was changed to handle timeout (optionally) and abort due to kill as signals which make signal slot occupied. - Renamed MDL_context::acquire_lock_impl() to acquire_lock(). Changed it to be able correctly process requests for shared locks when there are open HANDLERs, made this method more optimized for acquisition of shared locks. As part of this change moved code common between try_acquire_lock() and acquire_lock() to new try_acquire_lock_impl() method. Also adjusted acquire_lock()'s code to take into account the fact that in cases when lock is granted as result of MDL_context::reschedule_waiters() call (i.e. when it is granted after waiting for lock conflict to go away) updating MDL_lock state is responsibility of the thread calling reschedule_waiters(). - Changed MDL_context::find_deadlock() to send VICTIM signal even if victim is the context which has initiated deadlock detection. This is required in order to avoid races in cases when the same context simultaneously is chosen as a victim and its request for lock is satisfied. As result return value of this method became unnecessary and it was changed to return void. Adjusted MDL_lock::find_deadlock() method to take into account that now there can be a discrepancy between MDL_context::m_waiting_for value being set and real state of the ticket this member points to. - Renamed MDL_context::m_waiting_for_lock to m_LOCK_waiting_for and MDL_context::stop_waiting() to done_waiting_for(). - Finally, removed MDL_context::wait_for_lock() method. sql/mdl.h: Changed MDL subsystem to support new approach to acquring metadata locks in open tables and more fair and efficient scheduling of metadata locks. To implement this: - Members and methods of MDL_context related to sending and waiting for signal were moved to separate MDL_wait class. - Since now in order to avoid race conditions we must grant the lock only to the context which was not chosen as a victim of deadlock, killed or aborted due to timeout MDL_wait::set_status (former awake()) was changed not to send signal if signal slot is already occupied and to indicate this fact through its return value. Also NORMAL_WAKE_UP signal became GRANTED, and timeouts and aborts due to kill became full blown signals rather than simple return values. - MDL_wait::timed_wait() now takes extra parameter that indicates whether signal should be set if timeout is reached. - Enabled fast push_back() operation in MDL_context::m_tickets list to make move_ticket_after_trans_sentinel() method more efficient. - Removed MDL_context::wait_for_lock() method. - Renamed MDL_context::m_waiting_for_lock to m_LOCK_waiting_for and MDL_context::stop_waiting() to done_waiting_for(). - MDL_context::acquire_lock_impl() became acquire_lock(). - Introduced MDL_context::try_acquire_lock_impl() as a place for code shared by try_acquire_lock and acquire_lock(). - Due to fact that now VICTIM signal is sent even if victim is the context which has initiated deadlock detection find_deadlock() no longer needs a return value. sql/sql_base.cc: Implemented new approach to acquiring metadata locks in open_tables(). We no longer perform back-off when conflicting metadata lock is encountered. Instead we wait for this lock to go away while holding all locks which were acquired so far. Back-off is only used in situation when further waiting will cause a deadlock which could be avoided by performing back-off and restarting open_tables() process. Absence of waiting between back-off and restart of acquiring metadata locks can't lead to livelocks as MDL subsystem was changed to make release of lock and granting it to waiting lock an atomic action, so back-off will automatically give way to other participants of deadlock loop. Accordingly: - open_table_get_mdl_lock() and open_and_process_routine() were changed to wait for conflicting metadata lock to go away without back-off. Only if such wait leads to a deadlock back-off is requested. As part of this change new error handler class was introduced which converts, if possible, ER_LOCK_DEADLOCK error to a request for back-off and re-start of open_tables() process. - Open_table_context::recover_from_failed_open() was changed not to wait in case of metadata lock conflict. Instead we immediately proceed to re-acquiring locks. - Open_table_context::request_backoff_action() now always emits error if back-off is requested in the middle of transaction as we can't be sure that releasing lock which were acquired only by current statement will resolve a deadlock. Before this patch such situations were successfully detected thanks to the fact that we called MDL_context::wait_for_lock() method in recover_from_failed_open(). - In order to avoid deadlocks open_tables() code was adjusted to flush open HANDLERs for which there are pending requests for X locks before restarting the process of acquiring metadata locks. - Changed close_tables_for_reopen() not to reset MDL_request for tables belonging to the tail of prelocking list. It is no longer necessary as these MDL_request objects won't be used for any waiting. - Adjusted comment in tdc_wait_for_old_version() to avoid mentioning removed MDL_context::wait_for_lock() method. sql/sql_base.h: As we no longer wait for conflicting metadata lock away in Open_table_context::recover_from_failed_open() method, Open_table_context::OT_WAIT_MDL_LOCK action was renamed to OT_MDL_CONFLICT. Also Open_table_context::m_failed_mdl_request became unnecessary and was removed. sql/sql_plist.h: Extended I_P_List template to support efficient push_back() operation if it is parameterized with an appropriate policy class. sql/sql_show.cc: Adjusted code after removal of MDL_context::wait_for_lock() method. Now if one needs to acquire metadata lock with waiting one has to use a variant of MDL_context::acquire_lock() method.
2010-06-07 09:06:55 +02:00
TABLE_LIST *table);
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
bool can_recover_from_failed_open() const
{ return m_action != OT_NO_ACTION; }
/**
When doing a back-off, we close all tables acquired by this
statement. Return an MDL savepoint taken at the beginning of
the statement, so that we can rollback to it before waiting on
locks.
*/
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
const MDL_savepoint &start_of_statement_svp() const
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
{
return m_start_of_statement_svp;
}
inline ulong get_timeout() const
{
return m_timeout;
}
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Make open flags part of Open_table_context. This allows to simplify some code and (in future) enforce the invariant that we don't, say, request a back off on the table when there is MYSQL_OPEN_IGNORE_FLUSH flag. sql/sql_base.cc: open_table() flags are part of Open_table_context. Remove dead code that would check for OPEN_VIEW_NO_PARSE, which is not an open table flag. sql/sql_base.h: Move flags to Open_table_context. Reorder Open_table_context members to compact the structure footprint. sql/sql_insert.cc: Update with a new calling signature of open_table(). sql/sql_table.cc: Update with a new calling signature of open_table().
2010-06-01 12:49:35 +02:00
uint get_flags() const { return m_flags; }
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
/**
Set flag indicating that we have already acquired metadata lock
protecting this statement against GRL while opening tables.
*/
Added new MDL_BACKUP locks for all backup stages Part of MDEV-5336 Implement LOCK FOR BACKUP - Added new locks to MDL_BACKUP for all stages of backup locks and a new MDL lock needed for backup stages. - Renamed MDL_BACKUP_STMT to MDL_BACKUP_DDL - flush_tables() takes a new parameter that decides what should be flushed. - InnoDB, Aria (transactional tables with checksums), Blackhole, Federated and Federatedx tables are marked to be safe for online backup. We are using MDL_BACKUP_TRANS_DML instead of MDL_BACKUP_DML locks for these which allows any DML's to proceed for these tables during the whole backup process until BACKUP STAGE COMMIT which will block the final commit.
2018-11-06 16:05:24 +01:00
void set_has_protection_against_grl(enum_mdl_type mdl_type)
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
{
Added new MDL_BACKUP locks for all backup stages Part of MDEV-5336 Implement LOCK FOR BACKUP - Added new locks to MDL_BACKUP for all stages of backup locks and a new MDL lock needed for backup stages. - Renamed MDL_BACKUP_STMT to MDL_BACKUP_DDL - flush_tables() takes a new parameter that decides what should be flushed. - InnoDB, Aria (transactional tables with checksums), Blackhole, Federated and Federatedx tables are marked to be safe for online backup. We are using MDL_BACKUP_TRANS_DML instead of MDL_BACKUP_DML locks for these which allows any DML's to proceed for these tables during the whole backup process until BACKUP STAGE COMMIT which will block the final commit.
2018-11-06 16:05:24 +01:00
m_has_protection_against_grl|= MDL_BIT(mdl_type);
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
}
Added new MDL_BACKUP locks for all backup stages Part of MDEV-5336 Implement LOCK FOR BACKUP - Added new locks to MDL_BACKUP for all stages of backup locks and a new MDL lock needed for backup stages. - Renamed MDL_BACKUP_STMT to MDL_BACKUP_DDL - flush_tables() takes a new parameter that decides what should be flushed. - InnoDB, Aria (transactional tables with checksums), Blackhole, Federated and Federatedx tables are marked to be safe for online backup. We are using MDL_BACKUP_TRANS_DML instead of MDL_BACKUP_DML locks for these which allows any DML's to proceed for these tables during the whole backup process until BACKUP STAGE COMMIT which will block the final commit.
2018-11-06 16:05:24 +01:00
bool has_protection_against_grl(enum_mdl_type mdl_type) const
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
{
Added new MDL_BACKUP locks for all backup stages Part of MDEV-5336 Implement LOCK FOR BACKUP - Added new locks to MDL_BACKUP for all stages of backup locks and a new MDL lock needed for backup stages. - Renamed MDL_BACKUP_STMT to MDL_BACKUP_DDL - flush_tables() takes a new parameter that decides what should be flushed. - InnoDB, Aria (transactional tables with checksums), Blackhole, Federated and Federatedx tables are marked to be safe for online backup. We are using MDL_BACKUP_TRANS_DML instead of MDL_BACKUP_DML locks for these which allows any DML's to proceed for these tables during the whole backup process until BACKUP STAGE COMMIT which will block the final commit.
2018-11-06 16:05:24 +01:00
return (bool) (m_has_protection_against_grl & MDL_BIT(mdl_type));
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
}
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
private:
Fix for bug#14188793 - "DEADLOCK CAUSED BY ALTER TABLE DOEN'T CLEAR STATUS OF ROLLBACKED TRANSACTION" and bug #17054007 - "TRANSACTION IS NOT FULLY ROLLED BACK IN CASE OF INNODB DEADLOCK". The problem in the first bug report was that although deadlock involving metadata locks was reported using the same error code and message as InnoDB deadlock it didn't rollback transaction like the latter. This caused confusion to users as in some cases after ER_LOCK_DEADLOCK transaction could have been restarted immediately and in some cases rollback was required. The problem in the second bug report was that although InnoDB deadlock caused transaction rollback in all storage engines it didn't cause release of metadata locks. So concurrent DDL on the tables used in transaction was blocked until implicit or explicit COMMIT or ROLLBACK was issued in the connection which got InnoDB deadlock. The former issue has stemmed from the fact that when support for detection and reporting metadata locks deadlocks was added we erroneously assumed that InnoDB doesn't rollback transaction on deadlock but only last statement (while this is what happens on InnoDB lock timeout actually) and so didn't implement rollback of transactions on MDL deadlocks. The latter issue was caused by the fact that rollback of transaction due to deadlock is carried out by setting THD::transaction_rollback_request flag at the point where deadlock is detected and performing rollback inside of trans_rollback_stmt() call when this flag is set. And trans_rollback_stmt() is not aware of MDL locks, so no MDL locks are released. This patch solves these two problems in the following way: - In case when MDL deadlock is detect transaction rollback is requested by setting THD::transaction_rollback_request flag. - Code performing rollback of transaction if THD::transaction_rollback_request is moved out from trans_rollback_stmt(). Now we handle rollback request on the same level as we call trans_rollback_stmt() and release statement/ transaction MDL locks.
2013-08-20 11:12:34 +02:00
/* THD for which tables are opened. */
THD *m_thd;
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
/**
For OT_DISCOVER and OT_REPAIR actions, the table list element for
the table which definition should be re-discovered or which
should be repaired.
*/
TABLE_LIST *m_failed_table;
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
MDL_savepoint m_start_of_statement_svp;
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
/**
Lock timeout in seconds. Initialized to LONG_TIMEOUT when opening system
tables or to the "lock_wait_timeout" system variable for regular tables.
*/
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Make open flags part of Open_table_context. This allows to simplify some code and (in future) enforce the invariant that we don't, say, request a back off on the table when there is MYSQL_OPEN_IGNORE_FLUSH flag. sql/sql_base.cc: open_table() flags are part of Open_table_context. Remove dead code that would check for OPEN_VIEW_NO_PARSE, which is not an open table flag. sql/sql_base.h: Move flags to Open_table_context. Reorder Open_table_context members to compact the structure footprint. sql/sql_insert.cc: Update with a new calling signature of open_table(). sql/sql_table.cc: Update with a new calling signature of open_table().
2010-06-01 12:49:35 +02:00
ulong m_timeout;
/* open_table() flags. */
uint m_flags;
/** Back off action. */
enum enum_open_table_action m_action;
/**
Whether we had any locks when this context was created.
If we did, they are from the previous statement of a transaction,
and we can't safely do back-off (and release them).
*/
bool m_has_locks;
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
/**
Indicates that in the process of opening tables we have acquired
protection against global read lock.
*/
Added new MDL_BACKUP locks for all backup stages Part of MDEV-5336 Implement LOCK FOR BACKUP - Added new locks to MDL_BACKUP for all stages of backup locks and a new MDL lock needed for backup stages. - Renamed MDL_BACKUP_STMT to MDL_BACKUP_DDL - flush_tables() takes a new parameter that decides what should be flushed. - InnoDB, Aria (transactional tables with checksums), Blackhole, Federated and Federatedx tables are marked to be safe for online backup. We are using MDL_BACKUP_TRANS_DML instead of MDL_BACKUP_DML locks for these which allows any DML's to proceed for these tables during the whole backup process until BACKUP STAGE COMMIT which will block the final commit.
2018-11-06 16:05:24 +01:00
mdl_bitmap_t m_has_protection_against_grl;
A follow up patch for the fix for Bug#51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". Move declarations of sql_base.cc classes to sql_base.h (previously declared in sql_class.h). Became possible after a header file split. sql/sql_base.cc: Make sql_base.h the first include in sql_base.cc. sql/sql_base.h: Add declarations of Prelocking_strategy and Open_table_context. sql/sql_class.h: Remove declarations of Prelocking_strategy and Open_table_context (moved).
2010-06-01 12:19:05 +02:00
};
Applied all changes from Igor and Sanja
2013-06-15 17:32:08 +02:00
/**
Check if a TABLE_LIST instance represents a pre-opened temporary table.
*/
inline bool is_temporary_table(TABLE_LIST *tl)
{
if (tl->view || tl->schema_table)
return FALSE;
if (!tl->table)
return FALSE;
/*
NOTE: 'table->s' might be NULL for specially constructed TABLE
instances. See SHOW TRIGGERS for example.
*/
if (!tl->table->s)
return FALSE;
return tl->table->s->tmp_table != NO_TMP_TABLE;
}
Bug #56085 Embedded server tests fails with assert in check_if_table_exists() This assert was triggered when the server tried to load plugins while running in embedded server mode. In embedded server mode, check_if_table_exists() was used to check if mysql.plugin existed so that ER_NO_SUCH_TABLE could be silently ignored. The problem was that this check was done without acquiring a metadata lock on mysql.plugin first. This triggered the assert. This patch fixes the problem by removing the call to check_if_table_exists() from plugin_load(). Instead an error handler which traps ER_NO_SUCH_TABLE is installed before trying to open mysql.plugin when running in embedded server mode. No test coverage added since this assert was triggered by existing tests running in embedded server mode. sql/sql_base.cc: Renamed Prelock_error_handler to No_such_table_error_handler and moved the declaration to sql_base.h to make it usable in plugin_load(). sql/sql_base.h: Renamed Prelock_error_handler to No_such_table_error_handler and moved the declaration to sql_base.h to make it usable in plugin_load(). sql/sql_plugin.cc: Removed call to check_if_table_exists() used to check for mysql.plugin in plugin_load() for embedded server. Instead install error handler which traps ER_NO_SUCH_TABLE during open_and_lock_tables().
2010-08-19 11:33:37 +02:00
/**
This internal handler is used to trap ER_NO_SUCH_TABLE.
*/
class No_such_table_error_handler : public Internal_error_handler
{
public:
No_such_table_error_handler()
: m_handled_errors(0), m_unhandled_errors(0)
{}
bool handle_condition(THD *thd,
uint sql_errno,
const char* sqlstate,
MDEV-11597 Assertion when doing select from virtual column with impossible value - Changed error handlers interface so that they can change error level in the handler - Give warnings and errors when calculating virtual columns - On insert/update error is fatal in strict mode. - SELECT and DELETE will only give a warning if a virtual field generates an error - Added VCOL_UPDATE_FOR_DELETE and VCOL_UPDATE_INDEX_FOR_REPLACE to be able to easily detect in update_virtual_fields() if we should use an error handler to mask errors or not.
2017-01-10 17:28:24 +01:00
Sql_condition::enum_warning_level *level,
Bug #56085 Embedded server tests fails with assert in check_if_table_exists() This assert was triggered when the server tried to load plugins while running in embedded server mode. In embedded server mode, check_if_table_exists() was used to check if mysql.plugin existed so that ER_NO_SUCH_TABLE could be silently ignored. The problem was that this check was done without acquiring a metadata lock on mysql.plugin first. This triggered the assert. This patch fixes the problem by removing the call to check_if_table_exists() from plugin_load(). Instead an error handler which traps ER_NO_SUCH_TABLE is installed before trying to open mysql.plugin when running in embedded server mode. No test coverage added since this assert was triggered by existing tests running in embedded server mode. sql/sql_base.cc: Renamed Prelock_error_handler to No_such_table_error_handler and moved the declaration to sql_base.h to make it usable in plugin_load(). sql/sql_base.h: Renamed Prelock_error_handler to No_such_table_error_handler and moved the declaration to sql_base.h to make it usable in plugin_load(). sql/sql_plugin.cc: Removed call to check_if_table_exists() used to check for mysql.plugin in plugin_load() for embedded server. Instead install error handler which traps ER_NO_SUCH_TABLE during open_and_lock_tables().
2010-08-19 11:33:37 +02:00
const char* msg,
Applied all changes from Igor and Sanja
2013-06-15 17:32:08 +02:00
Sql_condition ** cond_hdl);
Bug #56085 Embedded server tests fails with assert in check_if_table_exists() This assert was triggered when the server tried to load plugins while running in embedded server mode. In embedded server mode, check_if_table_exists() was used to check if mysql.plugin existed so that ER_NO_SUCH_TABLE could be silently ignored. The problem was that this check was done without acquiring a metadata lock on mysql.plugin first. This triggered the assert. This patch fixes the problem by removing the call to check_if_table_exists() from plugin_load(). Instead an error handler which traps ER_NO_SUCH_TABLE is installed before trying to open mysql.plugin when running in embedded server mode. No test coverage added since this assert was triggered by existing tests running in embedded server mode. sql/sql_base.cc: Renamed Prelock_error_handler to No_such_table_error_handler and moved the declaration to sql_base.h to make it usable in plugin_load(). sql/sql_base.h: Renamed Prelock_error_handler to No_such_table_error_handler and moved the declaration to sql_base.h to make it usable in plugin_load(). sql/sql_plugin.cc: Removed call to check_if_table_exists() used to check for mysql.plugin in plugin_load() for embedded server. Instead install error handler which traps ER_NO_SUCH_TABLE during open_and_lock_tables().
2010-08-19 11:33:37 +02:00
/**
Returns TRUE if one or more ER_NO_SUCH_TABLE errors have been
trapped and no other errors have been seen. FALSE otherwise.
*/
bool safely_trapped_errors();
private:
int m_handled_errors;
int m_unhandled_errors;
};
WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h
2010-03-31 16:05:33 +02:00
#endif /* SQL_BASE_INCLUDED */
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