The reason why we have wsrep_on() at all is that the macro WSREP(thd)
depends on the definition of THD, and that is intentionally an opaque
data type for InnoDB. So, we cannot avoid invoking wsrep_on(), but
we can evaluate the less expensive conditions thd && WSREP_ON before
calling the function.
Global_read_lock: Use WSREP_NNULL(thd) instead of wsrep_on(thd)
because we not only know the definition of THD but also that
the pointer is not null.
wsrep_open(): Use WSREP(thd) instead of wsrep_on(thd).
InnoDB: Replace thd && wsrep_on(thd) with wsrep_on(thd), now that
the condition has been merged to the definition of the macro
wsrep_on().
With MDEV-19384 fixed FTWRL releases HANDLER locks early, which allows
concurrent threads to go. Test case may get stuck on FTWRL waiting for
LOCK TABLES.
The deadlock happened between FTWRL under open HANDLER, LOCK TABLE and
DROP DATABASE
Fixed by reverting the previous fix for handler open in
lock_global_read_lock()
Fixed the original (wrong) test case in flush_read_lock.test to be
repeatable.
local_global_read_lock did release all HANDLER's before taking its
MDL_BACKUP_FTWRL# locks. This had a potential race condition if
there was a waiting LOCK TABLE for one of the freed handlers.
Fixed by moving the release of HANDLER's to after the backup locks are
taken.
After commit 8cf7e3459 it's not anymore critical to free HANDLER's in
FTWRL, but we will keep the mysql_ha_cleanup_no_free() call until 10.5
to not cause any issues with 10.4 just before it's going GA.
Part of MDEV-5336 Implement LOCK FOR BACKUP
- Changed check of Global_only_lock to also include BACKUP lock.
- We store latest MDL_BACKUP_DDL lock in thd->mdl_backup_ticket to be able
to downgrade lock during copy_data_between_tables()
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.
Part of MDEV-5336 Implement LOCK FOR BACKUP
FLUSH TABLE table_names have changed slighty as we are now opening
tables before taking the MDL lock. The difference is that FLUSH TABLE
table_name will now be blocked by a table that is waiting for FTWRL.
There should not be any new deadlocks as part of this change.
The end result is still better in most cases as FTWRL is now only
waiting for write statements to end, not for read only statements and
it's not flushing tables in use from the table cache.
Share will be needed to be able to determine if table supports online
backup. Appropriate metadata lock type in BACKUP namespace will be
acquired basing on this information.
Also made pending global read lock request to be preferred victim of MDL
deadlock detector. This allows us to hide some non-fatal deadlocks and
make FTWRL less likely to break concurrent queries.
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
main.derived_cond_pushdown: Move all 10.3 tests to the end,
trim trailing white space, and add an "End of 10.3 tests" marker.
Add --sorted_result to tests where the ordering is not deterministic.
main.win_percentile: Add --sorted_result to tests where the
ordering is no longer deterministic.
MDEV-14831 CREATE OR REPLACE SEQUENCE under LOCK TABLE corrupts the
sequence, causes ER_KEY_NOT_FOUND
The problem was that sequence_insert didn't properly handle the case
where there where there was a LOCK TABLE while creating the sequence.
Fixed by opening the sequence table, for inserting the first record, in
a new environment without any other open tables.
Found also a bug in Locked_tables_list::reopen_tables() where the lock
structure for the new tables was allocated in THD::mem_root, which causes
crashes. This could cause problems with other create tables done under
LOCK TABLES.
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 "")
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
This was done to get more information about where time is spent.
Now we can get proper timing for time spent in commit, rollback,
binlog write etc.
Following stages was added:
- Commit
- Commit_implicit
- Rollback
- Rollback implicit
- Binlog write
- Init for update
- This is used instead of "Init" for insert, update and delete.
- Staring cleanup
Following stages where changed:
- "Unlocking tables" stage reset stage to previous stage at end
- "binlog write" stage resets stage to previous stage at end
- "end" -> "end of update loop"
- "cleaning up" -> "Reset for next command"
- Added stage_searching_rows_for_update when searching for rows
to be deleted.
Other things:
- Renamed all stages to start with big letter (before there was no
consitency)
- Increased performance_schema_max_stage_classes from 150 to 160.
- Most of the test changes in performance schema comes from renaming of
stages.
- Removed duplicate output of variables and inital state in a lot of
performance schema tests.
This was done to make it easier to change a default value for a
performance variable without affecting all tests.
- Added start_server_variables.test to check configuration
- Removed some duplicate "closing tables" stages
- Updated position for "stage_init_update" and "stage_updating" for
delete, insert and update to be just before update loop (for more
exact timing).
- Don't set "Checking permissions" twice in a row.
- Remove stage_end stage from creating views (not done for create table
either).
- Updated default performance history size from 10 to 20 because of new
stages
- Ensure that ps_enabled is correct (to be used in a later patch)
If compiling a non DBUG binary with
-DDBUG_ASSERT_AS_PRINTF asserts will be
changed to printf + stack trace (of stack
trace are enabled).
- Changed #ifndef DBUG_OFF to
#ifdef DBUG_ASSERT_EXISTS
for those DBUG_OFF that was just used to enable
assert
- Assert checking that could greatly impact
performance where changed to DBUG_ASSERT_SLOW which
is not affected by DBUG_ASSERT_AS_PRINTF
- Added one extra option to my_print_stacktrace() to
get more silent in case of stack trace printing as
part of assert.
- Added sql/mariadb.h file that should be included first by files in sql
directory, if sql_plugin.h is not used (sql_plugin.h adds SHOW variables
that must be done before my_global.h is included)
- Removed a lot of include my_global.h from include files
- Removed include's of some files that my_global.h automatically includes
- Removed duplicated include's of my_sys.h
- Replaced include my_config.h with my_global.h
bunch of bugs when external_lock() fails on unlock:
* mi_lock_database() used mi_mark_crashed() under share->intern_lock,
but mi_mark_crashed() itself locks this mutex.
* handler::close() required table to be unlocked, but failed
external_lock didn't count as unlock
* mysql_unlock_tables() ignored all unlock errors, but they still set
the error status in stmt_da.
Working features:
CREATE OR REPLACE [TEMPORARY] SEQUENCE [IF NOT EXISTS] name
[ INCREMENT [ BY | = ] increment ]
[ MINVALUE [=] minvalue | NO MINVALUE ]
[ MAXVALUE [=] maxvalue | NO MAXVALUE ]
[ START [ WITH | = ] start ] [ CACHE [=] cache ] [ [ NO ] CYCLE ]
ENGINE=xxx COMMENT=".."
SELECT NEXT VALUE FOR sequence_name;
SELECT NEXTVAL(sequence_name);
SELECT PREVIOUS VALUE FOR sequence_name;
SELECT LASTVAL(sequence_name);
SHOW CREATE SEQUENCE sequence_name;
SHOW CREATE TABLE sequence_name;
CREATE TABLE sequence-structure ... SEQUENCE=1
ALTER TABLE sequence RENAME TO sequence2;
RENAME TABLE sequence TO sequence2;
DROP [TEMPORARY] SEQUENCE [IF EXISTS] sequence_names
Missing features
- SETVAL(value,sequence_name), to be used with replication.
- Check replication, including checking that sequence tables are marked
not transactional.
- Check that a commit happens for NEXT VALUE that changes table data (may
already work)
- ALTER SEQUENCE. ANSI SQL version of setval.
- Share identical sequence entries to not add things twice to table list.
- testing insert/delete/update/truncate/load data
- Run and fix Alibaba sequence tests (part of mysql-test/suite/sql_sequence)
- Write documentation for NEXT VALUE / PREVIOUS_VALUE
- NEXTVAL in DEFAULT
- Ensure that NEXTVAL in DEFAULT uses database from base table
- Two NEXTVAL for same row should give same answer.
- Oracle syntax sequence_table.nextval, without any FOR or FROM.
- Sequence tables are treated as 'not read constant tables' by SELECT; Would
be better if we would have a separate list for sequence tables so that
select doesn't know about them, except if refereed to with FROM.
Other things done:
- Improved output for safemalloc backtrack
- frm_type_enum changed to Table_type
- Removed lex->is_view and replaced with lex->table_type. This allows
use to more easy check if item is view, sequence or table.
- Added table flag HA_CAN_TABLES_WITHOUT_ROLLBACK, needed for handlers
that want's to support sequences
- Added handler calls:
- engine_name(), to simplify getting engine name for partition and sequences
- update_first_row(), to be able to do efficient sequence implementations.
- Made binlog_log_row() global to be able to call it from ha_sequence.cc
- Added handler variable: row_already_logged, to be able to flag that the
changed row is already logging to replication log.
- Added CF_DB_CHANGE and CF_SCHEMA_CHANGE flags to simplify
deny_updates_if_read_only_option()
- Added sp_add_cfetch() to avoid new conflicts in sql_yacc.yy
- Moved code for add_table_options() out from sql_show.cc::show_create_table()
- Added String::append_longlong() and used it in sql_show.cc to simplify code.
- Added extra option to dd_frm_type() and ha_table_exists to indicate if
the table is a sequence. Needed by DROP SQUENCE to not drop a table.
Implementation of MDEV-7660 introduced unwanted incompatible change:
modifications under LOCK TABLES with autocommit enabled are rolled back on
disconnect. Previously everything was committed, because LOCK TABLES didn't
adjust autocommit setting.
This patch restores original behavior by reverting some changes done in
MDEV-7660:
- sql/sql_parse.cc: do not reset autocommit on LOCK TABLES
- sql/sql_base.cc: do not set autocommit on UNLOCK TABLES
- test cases: main.lock_tables_lost_commit, main.partition_explicit_prune,
rpl.rpl_switch_stm_row_mixed, tokudb.nested_txn_implicit_commit,
tokudb_bugs.db806
But it makes InnoDB tables under LOCK TABLES ... READ [LOCAL] not protected
against DML. To restore protection some changes from WL#6671 were merged,
specifically MDL_SHARED_READ_ONLY and test cases.
WL#6671 merge highlights:
- Not all tests merged.
- In MySQL LOCK TABLES ... READ acquires MDL_SHARED_READ_ONLY for all engines,
in MariaDB MDL_SHARED_READ is always acquired first and then upgraded to
MDL_SHARED_READ_ONLY for InnoDB only.
- The above allows us to omit MDL_SHARED_WRITE_LOW_PRIO implementation in
MariaDB, which is rather useless with InnoDB. In MySQL it is needed to
preserve locking behavior between low priority writes and LOCK TABLES ... READ
for non-InnoDB engines (covered by sys_vars.sql_low_priority_updates_func).
- Omitted HA_NO_READ_LOCAL_LOCK, we rely on lock_count() instead.
- Omitted "piglets": in MariaDB stream of DML against InnoDB table may lead to
concurrent LOCK TABLES ... READ starvation.
- HANDLER ... OPEN acquires MDL_SHARED_READ instead of MDL_SHARED in MariaDB.
- Omitted SNRW->X MDL lock upgrade for IMPORT/DISCARD TABLESPAECE under LOCK
TABLES.
- Omitted strong locks for views, triggers and SP under LOCK TABLES.
- Omitted IX schema lock for LOCK TABLES READ.
- Omitted deadlock weight juggling for LOCK TABLES.
Full WL#6671 merge status:
- innodb.innodb-lock: fully merged
- main.alter_table: not merged due to different HANDLER solution
- main.debug_sync: fully merged
- main.handler_innodb: not merged due to different HANDLER solution
- main.handler_myisam: not merged due to different HANDLER solution
- main.innodb_mysql_lock: fully merged
- main.insert_notembedded: fully merged
- main.lock: not merged (due to no strong locks for views)
- main.lock_multi: not merged
- main.lock_sync: fully merged (partially in MDEV-7660)
- main.mdl_sync: not merged
- main.partition_debug_sync: not merged due to different HANDLER solution
- main.status: fully merged
- main.view: fully merged
- perfschema.mdl_func: not merged (no such test in MariaDB)
- perfschema.table_aggregate_global_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_global_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_global_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_global_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_hist_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_hist_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_hist_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_hist_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_thread_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_thread_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_thread_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_thread_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_global_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_global_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_global_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_global_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_hist_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_hist_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_hist_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_hist_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_thread_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_thread_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_thread_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_thread_4u_3t: not merged (didn't fail in MariaDB)
- sys_vars.sql_low_priority_updates_func: not merged
- include/thr_rwlock.h: not merged, rw_pr_lock_assert_write_owner and
rw_pr_lock_assert_not_write_owner are macros in MariaDB
- sql/handler.h: not merged (HA_NO_READ_LOCAL_LOCK)
- sql/mdl.cc: partially merged (MDL_SHARED_READ_ONLY only)
- sql/mdl.h: partially merged (MDL_SHARED_READ_ONLY only)
- sql/lock.cc: fully merged
- sql/sp_head.cc: not merged
- sql/sp_head.h: not merged
- sql/sql_base.cc: partially merged (MDL_SHARED_READ_ONLY only)
- sql/sql_base.h: not merged
- sql/sql_class.cc: fully merged
- sql/sql_class.h: fully merged
- sql/sql_handler.cc: merged partially (different solution in MariaDB)
- sql/sql_parse.cc: partially merged, mostly omitted low priority write part
- sql/sql_reload.cc: not merged comment change
- sql/sql_table.cc: not merged SNRW->X upgrade for IMPORT/DISCARD TABLESPACE
- sql/sql_view.cc: not merged
- sql/sql_yacc.yy: not merged (MDL_SHARED_WRITE_LOW_PRIO, MDL_SHARED_READ_ONLY)
- sql/table.cc: not merged (MDL_SHARED_WRITE_LOW_PRIO)
- sql/table.h: not merged (MDL_SHARED_WRITE_LOW_PRIO)
- sql/trigger.cc: not merged
- storage/innobase/handler/ha_innodb.cc: merged store_lock()/lock_count()
changes (in MDEV-7660), didn't merge HA_NO_READ_LOCAL_LOCK
- storage/innobase/handler/ha_innodb.h: fully merged in MDEV-7660
- storage/myisammrg/ha_myisammrg.cc: not merged comment change
- storage/perfschema/table_helper.cc: not merged (no MDL support in MariaDB PFS)
- unittest/gunit/mdl-t.cc: not merged
- unittest/gunit/mdl_sync-t.cc: not merged
MariaDB specific changes:
- handler.heap: different HANDLER solution, MDEV-7660
- handler.innodb: different HANDLER solution, MDEV-7660
- handler.interface: different HANDLER solution, MDEV-7660
- handler.myisam: different HANDLER solution, MDEV-7660
- main.mdl_sync: MDEV-7660 specific changes
- main.partition_debug_sync: removed test due to different HANDLER solution,
MDEV-7660
- main.truncate_coverage: removed test due to different HANDLER solution,
MDEV-7660
- mysql-test/include/mtr_warnings.sql: additional cleanup, MDEV-7660
- mysql-test/lib/v1/mtr_report.pl: additional cleanup, MDEV-7660
- plugin/metadata_lock_info/metadata_lock_info.cc: not in MySQL
- sql/sql_handler.cc: MariaDB specific fix for mysql_ha_read(), MDEV-7660
