- Initialize variables that could be used uninitialized
- Added extra end space to DbugStringItemTypeValue to get rid of warnings
from c_ptr()
- Session_sysvars_tracker::update() accessed unitialized memory if called
with NULL value.
- get_schema_stat_record() accessed unitialized memory if HA_KEY_LONG_HASH
was used
- parse_vcol_defs() accessed random memory for tables without keys.
Problem:
========
gcc 8 -O2 seems to indicate a real error for this code:
direct_pos= table->file->ha_table_flags() & HA_PRIMARY_KEY_REQUIRED_FOR_POSITION;
the warning: /mariadb/10.4/sql/rpl_gtid.cc:980:7:
warning: 'direct_pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
Analysis:
=========
'direct_pos' is a variable which holds 'table_flags'. If this flag is set it means
that a record within a table can be directly located by using its position. If
this flag is set to '0' means there is no direct access is available, hence
index scan must be initiated to locate the record. This direct_pos is used to
locate a row within mysql.gtid_slave_pos table for deletion.
Prior to the initialization of 'direct_pos' following steps take place.
1. mysql.gtid_slave_pos table is opened and 'table_opened' flag is set to true.
2. State check for mysql.gtid_slave_pos table is initiated.
If there is a failure during step2 code will be redirected to the error handling
part. This error handling code will access uninitialized value of 'direct_pos'.
This results in above mentioned warning.
Another issue found during analysis is the error handling code uses '!direct_pos'
to identify if the index is initialized or not. This is incorrect.
The index initialization code is shown below.
if (!direct_pos && (err= table->file->ha_index_init(0, 0)))
{
table->file->print_error(err, MYF(0));
goto end;
}
In case there is a failure during ha_index_init code will be redirected to end
part which tries to close the uninitialized index. It will result in an assert
10.4/sql/handler.h:3186: int handler::ha_index_end(): Assertion `inited==INDEX'
failed.
Fix:
===
Introduce a new variable named 'index_inited'. Set this variable upon successful
initialization of index initialization otherwise by default it is false. Use
this variable during error handling.
This patch changes how old rows in mysql.gtid_slave_pos* tables are deleted.
Instead of doing it as part of every replicated transaction in
record_gtid(), it is done periodically (every @@gtid_cleanup_batch_size
transaction) in the slave background thread.
This removes the deletion step from the replication process in SQL or worker
threads, which could speed up replication with many small transactions. It
also decreases contention on the global mutex LOCK_slave_state. And it
simplifies the logic, eg. when a replicated transaction fails after having
deleted old rows.
With this patch, the deletion of old GTID rows happens asynchroneously and
slightly non-deterministic. Thus the number of old rows in
mysql.gtid_slave_pos can temporarily exceed @@gtid_cleanup_batch_size. But
all old rows will be deleted eventually after sufficiently many new GTIDs
have been replicated.
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.
The test and also rpl_gtid_delete_domain failed on PPC64 platform
due to an incorrectly specified actual key for searching
in a gtid domain system hash. While the correct size is 32 bits
the supplied value was 8 bytes of long int size on the platform.
The problem became evident thanks to the big endiness which
cut off the *least* significant part of the value field.
Fixed with correcting a dynamic array initialization to hold
now uint32 values as well as the values extraction for
searching in the gtid domain system hash.
A new added test ensures no overflowed values are accepted
for deletion which prevents inadvertent action. Notice though
MariaDB [test]> set @@session.gtid_domain_id=(1 << 32) + 1;
MariaDB [test]> show warnings;
+---------+------+--------------------------------------------------------+
| Level | Code | Message |
+---------+------+--------------------------------------------------------+
| Warning | 1292 | Truncated incorrect gtid_domain_id value: '4294967297' |
+---------+------+--------------------------------------------------------+
MariaDB [test]> select @@session.gtid_domain_id;
+--------------------------+
| @@session.gtid_domain_id |
+--------------------------+
| 4294967295 |
+--------------------------+
This would happen especially in optimistic parallel replication, where there
is a good chance that a transaction will be rolled back (due to conflicts)
after it has executed record_gtid(). If the transaction did any deletions of
old rows as part of record_gtid(), those deletions will be undone as well.
And the code did not properly ensure that the deletions would be re-tried.
This patch makes record_gtid() remember the list of deletions done as part
of a transaction. Then in rpl_slave_state::update() when the changes have
been committed, we discard the list. However, in case of error and rollback,
in cleanup_context() we will instead put the list back into
rpl_global_gtid_slave_state so that the deletions will be re-tried later.
Probably fixes part of the cause of MDEV-12147 as well.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
This is a merge from 10.2, but the 10.2 version of this will not
be pushed into 10.2 yet, because the 10.2 version would include
backports of MDEV-14717 and MDEV-14585, which would introduce
a crash recovery regression: Tables could be lost on
table-rebuilding DDL operations, such as ALTER TABLE,
OPTIMIZE TABLE or this new backup-friendly TRUNCATE TABLE.
The test innodb.truncate_crash occasionally loses the table due to
the following bug:
MDEV-17158 log_write_up_to() sometimes fails
Implement undo tablespace truncation via normal redo logging.
Implement TRUNCATE TABLE as a combination of RENAME to #sql-ib name,
CREATE, and DROP.
Note: Orphan #sql-ib*.ibd may be left behind if MariaDB Server 10.2
is killed before the DROP operation is committed. If MariaDB Server 10.2
is killed during TRUNCATE, it is also possible that the old table
was renamed to #sql-ib*.ibd but the data dictionary will refer to the
table using the original name.
In MariaDB Server 10.3, RENAME inside InnoDB is transactional,
and #sql-* tables will be dropped on startup. So, this new TRUNCATE
will be fully crash-safe in 10.3.
ha_mroonga::wrapper_truncate(): Pass table options to the underlying
storage engine, now that ha_innobase::truncate() will need them.
rpl_slave_state::truncate_state_table(): Before truncating
mysql.gtid_slave_pos, evict any cached table handles from
the table definition cache, so that there will be no stale
references to the old table after truncating.
== TRUNCATE TABLE ==
WL#6501 in MySQL 5.7 introduced separate log files for implementing
atomic and crash-safe TRUNCATE TABLE, instead of using the InnoDB
undo and redo log. Some convoluted logic was added to the InnoDB
crash recovery, and some extra synchronization (including a redo log
checkpoint) was introduced to make this work. This synchronization
has caused performance problems and race conditions, and the extra
log files cannot be copied or applied by external backup programs.
In order to support crash-upgrade from MariaDB 10.2, we will keep
the logic for parsing and applying the extra log files, but we will
no longer generate those files in TRUNCATE TABLE.
A prerequisite for crash-safe TRUNCATE is a crash-safe RENAME TABLE
(with full redo and undo logging and proper rollback). This will
be implemented in MDEV-14717.
ha_innobase::truncate(): Invoke RENAME, create(), delete_table().
Because RENAME cannot be fully rolled back before MariaDB 10.3
due to missing undo logging, add some explicit rename-back in
case the operation fails.
ha_innobase::delete(): Introduce a variant that takes sqlcom as
a parameter. In TRUNCATE TABLE, we do not want to touch any
FOREIGN KEY constraints.
ha_innobase::create(): Add the parameters file_per_table, trx.
In TRUNCATE, the new table must be created in the same transaction
that renames the old table.
create_table_info_t::create_table_info_t(): Add the parameters
file_per_table, trx.
row_drop_table_for_mysql(): Replace a bool parameter with sqlcom.
row_drop_table_after_create_fail(): New function, wrapping
row_drop_table_for_mysql().
dict_truncate_index_tree_in_mem(), fil_truncate_tablespace(),
fil_prepare_for_truncate(), fil_reinit_space_header_for_table(),
row_truncate_table_for_mysql(), TruncateLogger,
row_truncate_prepare(), row_truncate_rollback(),
row_truncate_complete(), row_truncate_fts(),
row_truncate_update_system_tables(),
row_truncate_foreign_key_checks(), row_truncate_sanity_checks():
Remove.
row_upd_check_references_constraints(): Remove a check for
TRUNCATE, now that the table is no longer truncated in place.
The new test innodb.truncate_foreign uses DEBUG_SYNC to cover some
race-condition like scenarios. The test innodb-innodb.truncate does
not use any synchronization.
We add a redo log subformat to indicate backup-friendly format.
MariaDB 10.4 will remove support for the old TRUNCATE logging,
so crash-upgrade from old 10.2 or 10.3 to 10.4 will involve
limitations.
== Undo tablespace truncation ==
MySQL 5.7 implements undo tablespace truncation. It is only
possible when innodb_undo_tablespaces is set to at least 2.
The logging is implemented similar to the WL#6501 TRUNCATE,
that is, using separate log files and a redo log checkpoint.
We can simply implement undo tablespace truncation within
a single mini-transaction that reinitializes the undo log
tablespace file. Unfortunately, due to the redo log format
of some operations, currently, the total redo log written by
undo tablespace truncation will be more than the combined size
of the truncated undo tablespace. It should be acceptable
to have a little more than 1 megabyte of log in a single
mini-transaction. This will be fixed in MDEV-17138 in
MariaDB Server 10.4.
recv_sys_t: Add truncated_undo_spaces[] to remember for which undo
tablespaces a MLOG_FILE_CREATE2 record was seen.
namespace undo: Remove some unnecessary declarations.
fil_space_t::is_being_truncated: Document that this flag now
only applies to undo tablespaces. Remove some references.
fil_space_t::is_stopping(): Do not refer to is_being_truncated.
This check is for tablespaces of tables. Potentially used
tablespaces are never truncated any more.
buf_dblwr_process(): Suppress the out-of-bounds warning
for undo tablespaces.
fil_truncate_log(): Write a MLOG_FILE_CREATE2 with a nonzero
page number (new size of the tablespace in pages) to inform
crash recovery that the undo tablespace size has been reduced.
fil_op_write_log(): Relax assertions, so that MLOG_FILE_CREATE2
can be written for undo tablespaces (without .ibd file suffix)
for a nonzero page number.
os_file_truncate(): Add the parameter allow_shrink=false
so that undo tablespaces can actually be shrunk using this function.
fil_name_parse(): For undo tablespace truncation,
buffer MLOG_FILE_CREATE2 in truncated_undo_spaces[].
recv_read_in_area(): Avoid reading pages for which no redo log
records remain buffered, after recv_addr_trim() removed them.
trx_rseg_header_create(): Add a FIXME comment that we could write
much less redo log.
trx_undo_truncate_tablespace(): Reinitialize the undo tablespace
in a single mini-transaction, which will be flushed to the redo log
before the file size is trimmed.
recv_addr_trim(): Discard any redo logs for pages that were
logged after the new end of a file, before the truncation LSN.
If the rec_list becomes empty, reduce n_addrs. After removing
any affected records, actually truncate the file.
recv_apply_hashed_log_recs(): Invoke recv_addr_trim() right before
applying any log records. The undo tablespace files must be open
at this point.
buf_flush_or_remove_pages(), buf_flush_dirty_pages(),
buf_LRU_flush_or_remove_pages(): Add a parameter for specifying
the number of the first page to flush or remove (default 0).
trx_purge_initiate_truncate(): Remove the log checkpoints, the
extra logging, and some unnecessary crash points. Merge the code
from trx_undo_truncate_tablespace(). First, flush all to-be-discarded
pages (beyond the new end of the file), then trim the space->size
to make the page allocation deterministic. At the only remaining
crash injection point, flush the redo log, so that the recovery
can be tested.
Fixed by deleting the sequence if we where not able to initialize it
I also noticed that we didn't always set the error message when
check_killed(), which could lead to aborted queries without error
beeing properly set. Fixed by default setting error message if
check_error() noticed that killed had been called.
This allowed me to remove a lot of calls to thd->send_kill_message().
This preserves const str for constant strings
Other things
- A few variables where changed from LEX_STRING to LEX_CSTRING
- Incident_log_event::Incident_log_event and record_incident where
changed to take LEX_CSTRING* as an argument instead of LEX_STRING
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 things, mainly to get
create_mysqld_error_find_printf_error tool to work:
- Added protection to not include mysqld_error.h twice
- Include "unireg.h" instead of "mysqld_error.h" in server
- Added protection if ER_XX messages are already defined
- Removed wrong calls to my_error(ER_OUTOFMEMORY) as
my_malloc() and my_alloc will do this automatically
- Added missing %s to ER_DUP_QUERY_NAME
- Removed old and wrong calls to my_strerror() when using
MY_ERROR_ON_RENAME (wrong merge)
- Fixed deadlock error message from Galera. Before the extra
information given to ER_LOCK_DEADLOCK was missing because
ER_LOCK_DEADLOCK doesn't provide any extra information.
I kept #ifdef mysqld_error_find_printf_error_used in sql_acl.h
to make it easy to do this kind of check again in the future
Main problem was that no log-event print function checked for disk
full error on the IO_CACHE.
All changes in this patch only affects mysqlbinlog, not the server!
- Changed all log-event print functions to return 1 on error
- Fixed memory usage when not using --flashback.
- Added printing of number of rows in row events. Can be disabled with
--print-row-count=0
- Print annotated rows when using mysqlbinlog --short-form
- Fixed that mysqlbinlog --debug works
- Fixed create_drop_binlog.test test failure
- Reorganized fields in PRINT_EVENT_INFO to be according to size to
optimize storage
- Don't change print_row_event_position or print_row_counts if set by user
- Remove some testing of argument to my_free is 0
- base64-output=never is now supported and works in all context
- Updated help information for --base64-output and --short-form
- print_row_count is now on by default. Reset automatically if --short-form
is used
- Removed obsolote warning for mysql 5.6.0
- More DBUG_PRINT for mysqltest.cc
- my_b_write_byte() now checks for flush failures. This fixed a memory
overrun on disk full
- my_b_printf() now returns 1 on failure, 0 on ok. This simplifies code
and no old code was using the old return value of my_b_printf().
- my_b_Write_backtick_quote() now returns 1 on failure and 0 on ok
- Fixed some error conditions in log printing that was not previously
handled.
- Slave_rows_error_report() can now handle longlong positions
- Write_on_release_cache() rewritten so that we can detect errors
on flush. Not depending on automatic release anymore.
- Changed types for Pos and End_log_pos to 64 bit in SHOW BINLOG EVENTS
- Fixed that copy_event_cache_to_string_and_reinit() works with strings
longer than 4G (Changed to use LEX_STRING instead of String)
- Restricted binlog_rows_event_max_size to UINT32_MAX-1 as String's are
anyway restricted to UINT32_MAX
- Fixed bug in rpl_binlog_state::write_to_iocache() which hide write
failures (duplicate variable name)
- Fixed bug in String::append if original string was not allocated
- Stop mysqlbinlog output at once if there is an error.
- Before printing error message, flush result file. This ensures that
the error message is printed last. (Easier to find)
As reported in MDEV-11969 "there's no way to ditch knowledge" about some
domain that is no longer updated on a server. Besides being of annoyance to
clutter output in DBA console stale domains can prevent the slave
to connect the master as MDEV-12012 witnesses.
What domain is obsolete must be evaluated by the user (DBA) according
to whether the domain info is still relevant and will the domain ever
receive any update.
This patch introduces a method to discard obsolete gtid domains from
the server binlog state. The removal requires no event group from such
domain present in existing binlog files though. If there are any the
containing logs must be first PURGEd in order for
FLUSH BINARY LOGS DELETE_DOMAIN_ID=(list-of-domains)
succeed. Otherwise the command returns an error.
The list of obsolete domains can be computed through
intersecting two sets - the earliest (first) binlog's Gtid_list
and the current value of @@global.gtid_binlog_state - and extracting
the domain id components from the intersection list items.
The new DELETE_DOMAIN_ID featured FLUSH continues to rotate binlog
omitting the deleted domains from the active binlog file's Gtid_list.
Notice though when the command is ineffective - that none of requested to delete
domain exists in the binlog state - rotation does not occur.
Obsolete domain deletion is not harmful for connected slaves as long
as master side binlog files *purge* is synchronized with FLUSH-DELETE_DOMAIN_ID.
The slaves must have the last event from purged files processed as usual,
in order not to bump later into requesting a gtid from a file which
was already gone.
While the command is not replicated (as ordinary FLUSH BINLOG LOGS is)
slaves, even though having extra domains, won't suffer from reconnection errors
thanks to master-slave gtid connection protocol allowing the master
to be ignorant about a gtid domain.
Should at failover such slave to be promoted into master role it may run
the ex-master's
FLUSH BINARY LOGS DELETE_DOMAIN_ID=(list-of-domains)
to clean its own binlog state.
NOTES.
suite/perfschema/r/start_server_low_digest.result
is re-recorded as consequence of internal parser codes changes.
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
Do not silence uncertain cases, or fix any bugs.
The only functional change should be that ha_federated::extra()
is not calling DBUG_PRINT to report an unhandled case for
HA_EXTRA_PREPARE_FOR_DROP.
Intermediate commit.
Fix compilation failure with different my_atomic implementation.
The my_atomic_loadptr* takes void ** as first argument, so variables
updated with it needs to be void * (it is not legal C to cast
some_type ** to void **).
Intermediate commit.
Implement status variables to aid the DBA in determining the need
and/or effectiveness of the per-engine mylsq.gtid_slave_pos feature:
transactions_multi_engine
Number of transactions that changed data in multiple (transactional)
storage engines.
rpl_transactions_multi_engine
Number of replicated transactions that involved changes in multiple
(transactional) storage engines, before considering the update of the
mysql.gtid_slave_posXXX table.
transactions_gtid_foreign_engine
Number of replicated transactions where the update of the
mysql.gtid_slave_posXXX table had to choose a storage engine that did not
otherwise participate in the transaction.
Intermediate commit.
Fix record_gtid()'s choice of mysql.gtid_slave_pos* table to only consider
engines that participated in the transaction with write operations (ie.
ignore read-only participation).
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)
Intermediate commit.
Fix incorrect assertion. The hton in the list of pending GTIDs can be
NULL, in the special case where we failed to load the
mysql.gtid_slave_pos table at server startup, but nevertheless allow
non-GTID replication to proceed.
Intermediate commit.
Implement auto-creation of mysql.gtid_slave_pos* tables with needed engines,
if listed in --gtid-pos-auto-engines.
Uses an asynchronous approach to minimise locking overhead.
The list of available tables is extended with a flag. Extra entries are
added for --gtid-pos-auto-engines tables that do not exist yet, marked as
not existing but ready for auto-creation.
If record_gtid() needs a table marked for auto-creation, it sends a request
to the slave background thread to create the table, and continues to use an
existing table for the current and immediately coming transactions.
As soon as the slave background thread has made the new table available, it
will be used for all subsequent relevant transactions in record_gtid().
This asynchronous approach also avoids a lot of complex issues around trying
to do DDL in the middle of an on-going transaction.
Intermediate commit.
This commit implements that record_gtid() selects a gtid_slave_posXXX table
with a storage engine already in use by current transaction, if any.
The default table mysql.gtid_slave_pos is used if no match can be found on
storage engine, or for GTID position updates with no specific storage
engine.
Table discovery of mysql.gtid_slave_pos* happens on initial GTID state load
as well as on every START SLAVE. Some effort is made to make this possible
without additional locking. New tables are added using lock-free atomics.
Removing tables requires stopping all slaves first. A warning is given in
the error log when a table is removed but a non-stopped slave still has a
reference to it.
If multiple mysql.gtid_slave_posXXX tables with same storage engine exist,
one is chosen arbitrarily to be used, with a warning in the error log. GTID
data from all tables is still read, but only one among redundant tables with
same storage engine will be updated.
Intermediate commit.
When deleting old GTIDs, only pick those GTIDs that were recorded using the
same engine.
(Currently this is not used, there is only one table/engine active. This is
in preparation for extending record_gtid to pick the table with the same
engine as the active transaction, if any).
Intermediate commit.
For each GTID recorded in mysq.gtid_slave_pos, keep track of which
engine the update was made in.
This will be later used to know which rows can be deleted in the table
of a given engine.
Intermediate commit.
Keep track of which mysql.gtid_slave_posXXX tables are available for each
engine, by searching for all tables in the mysql schema with names that
start with "gtid_slave_pos".
The list is computed at server start when the GTID position is loaded, and
it is re-computed on every START SLAVE command. This way, the DBA can
manually add a table for a new engine, and it will be automatically picked
up on next START SLAVE, so a full server restart is not needed.
The list is not yet actually used in the code.
