to allow temp table operations) -- prerequisite patch #2.
Introduce a new form of find_temporary_table() function:
find_temporary_table() by a table key. It will be used
in further patches.
Replace find_temporary_table(table_list->db, table_list->name)
by more appropiate find_temporary_table(table_list) across
the codebase.
to allow temp table operations) -- prerequisite patch #2.
Introduce a new form of find_temporary_table() function:
find_temporary_table() by a table key. It will be used
in further patches.
Replace find_temporary_table(table_list->db, table_list->name)
by more appropiate find_temporary_table(table_list) across
the codebase.
temp table
This patch introduces two key changes in the replication's behavior.
Firstly, it reverts part of BUG#51894 which puts any update to temporary tables
into the trx-cache. Now, updates to temporary tables are handled according to
the type of their engines as a regular table.
Secondly, an unsafe mixed statement, (i.e. a statement that access transactional
table as well non-transactional or temporary table, and writes to any of them),
are written into the trx-cache in order to minimize errors in the execution when
the statement logging format is in use.
Such changes has a direct impact on which statements are classified as unsafe
statements and thus part of BUG#53259 is reverted.
temp table
This patch introduces two key changes in the replication's behavior.
Firstly, it reverts part of BUG#51894 which puts any update to temporary tables
into the trx-cache. Now, updates to temporary tables are handled according to
the type of their engines as a regular table.
Secondly, an unsafe mixed statement, (i.e. a statement that access transactional
table as well non-transactional or temporary table, and writes to any of them),
are written into the trx-cache in order to minimize errors in the execution when
the statement logging format is in use.
Such changes has a direct impact on which statements are classified as unsafe
statements and thus part of BUG#53259 is reverted.
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().
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.
corruption on ADD PARTITION and LOCK TABLE
Bug#53770: Server crash at handler.cc:2076 on
LOAD DATA after timed out COALESCE PARTITION
5.5 fix for:
Bug#51042: REORGANIZE PARTITION can leave table in an
inconsistent state in case of crash
Needs to be back-ported to 5.1
5.5 fix for:
Bug#50418: DROP PARTITION does not interact with
transactions
Main problem was non-persistent operations done
before meta-data lock was taken (53770+53676).
And 53676 needed to keep the table/partitions opened and locked
while copying the data to the new partitions.
Also added thorough tests to spot some additional bugs
in the ddl_log code, which could result in bad state
between the .frm and partitions.
Collapsed patch, includes all fixes required from the reviewers.
mysql-test/r/partition_innodb.result:
updated result with new test
mysql-test/suite/parts/inc/partition_crash.inc:
crash test include file
mysql-test/suite/parts/inc/partition_crash_add.inc:
test all states in fast_alter_partition_table
ADD PARTITION branch
mysql-test/suite/parts/inc/partition_crash_change.inc:
test all states in fast_alter_partition_table
CHANGE PARTITION branch
mysql-test/suite/parts/inc/partition_crash_drop.inc:
test all states in fast_alter_partition_table
DROP PARTITION branch
mysql-test/suite/parts/inc/partition_fail.inc:
recovery test including injecting errors
mysql-test/suite/parts/inc/partition_fail_add.inc:
test all states in fast_alter_partition_table
ADD PARTITION branch
mysql-test/suite/parts/inc/partition_fail_change.inc:
test all states in fast_alter_partition_table
CHANGE PARTITION branch
mysql-test/suite/parts/inc/partition_fail_drop.inc:
test all states in fast_alter_partition_table
DROP PARTITION branch
mysql-test/suite/parts/inc/partition_mgm_crash.inc:
include file that runs all crash and failure injection tests.
mysql-test/suite/parts/r/partition_debug_innodb.result:
new test result file
mysql-test/suite/parts/r/partition_debug_myisam.result:
new test result file
mysql-test/suite/parts/r/partition_special_innodb.result:
updated result
mysql-test/suite/parts/r/partition_special_myisam.result:
updated result
mysql-test/suite/parts/t/partition_debug_innodb-master.opt:
opt file for using with crashing tests of partitioned innodb
mysql-test/suite/parts/t/partition_debug_innodb.test:
partitioned innodb test that require debug builds
mysql-test/suite/parts/t/partition_debug_myisam-master.opt:
opt file for using with crashing tests of partitioned myisam
mysql-test/suite/parts/t/partition_debug_myisam.test:
partitioned myisam test that require debug builds
mysql-test/suite/parts/t/partition_special_innodb-master.opt:
added innodb-file-per-table to easier verify partition status on disk
mysql-test/suite/parts/t/partition_special_innodb.test:
added test case
mysql-test/suite/parts/t/partition_special_myisam.test:
added test case
mysql-test/t/partition_innodb.test:
added test case
sql/sql_base.cc:
Moved alter_close_tables to sql_partition.cc
sql/sql_base.h:
removed some non existing and duplicated functions.
sql/sql_partition.cc:
fast_alter_partition_table:
Spletted abort_and_upgrad_lock_and_close_table
to its parts (wait_while_table_is_used and
alter_close_tables) and always have
wait_while_table_is_used before any persistent
operations (including logs, which will be executed
on failure) and alter_close_tables after
create/read/write operations and before
drop operations.
moved alter_close_tables here from sql_base.cc
Added error injections for better test coverage.
write_log_final_change_partition:
fixed a log_entry linking bug (delete_frm was not
linked to change/drop partition)
and drop partition must be executed before
change partition (change partition can rename a
partition to an old name, like REORG p1 INTO (p1,p2).
write_log_add_change_partition:
need to use drop_frm first, and relinking that entry
and reusing its execute entry.
sql/sql_table.cc:
added initialization of next_active_log_entry.
sql/table.h:
removed a duplicate declaration.
corruption on ADD PARTITION and LOCK TABLE
Bug#53770: Server crash at handler.cc:2076 on
LOAD DATA after timed out COALESCE PARTITION
5.5 fix for:
Bug#51042: REORGANIZE PARTITION can leave table in an
inconsistent state in case of crash
Needs to be back-ported to 5.1
5.5 fix for:
Bug#50418: DROP PARTITION does not interact with
transactions
Main problem was non-persistent operations done
before meta-data lock was taken (53770+53676).
And 53676 needed to keep the table/partitions opened and locked
while copying the data to the new partitions.
Also added thorough tests to spot some additional bugs
in the ddl_log code, which could result in bad state
between the .frm and partitions.
Collapsed patch, includes all fixes required from the reviewers.
Remove acquisition of LOCK_open around file system operations,
since such operations are now protected by metadata locks.
Rework table discovery algorithm to not require LOCK_open.
No new tests added since all MDL locking operations are covered
in lock.test and mdl_sync.test, and as long as these tests
pass despite the increased concurrency, consistency must be
unaffected.
mysql-test/t/disabled.def:
Disable NDB tests due to Bug#55799.
sql/datadict.cc:
No longer necessary to protect ha_create_table() with
LOCK_open. Serial execution is now ensured by metadata
locks.
sql/ha_ndbcluster.cc:
Do not manipulate with LOCK_open in cluster code.
sql/ha_ndbcluster_binlog.cc:
Do not manipulate with LOCK_open in cluster code.
sql/ha_ndbcluster_binlog.h:
Update function signature.
sql/handler.cc:
Implement ha_check_if_table_exists().
@todo: some engines provide ha_table_exists_in_engine()
handlerton call, for those we perhaps shouldn't
call ha_discover(), to be more efficient.
Since currently it's only NDB, postpone till
integration with NDB.
sql/handler.h:
Declare ha_check_if_table_exists() function.
sql/mdl.cc:
Remove an obsolete comment.
sql/sql_base.cc:
Update to a new signature of close_cached_tables():
from now on we always call it without LOCK_open.
Update comments.
Remove get_table_share_with_create(), we should
not attempt to create a table under LOCK_open.
Introduce get_table_share_with_discover() instead,
which would request a back off action if the table
exists in engine.
Remove acquisition of LOCK_open for
data dictionary operations, such as check_if_table_exists().
Do not use get_table_share_with_create/discover for views,
where it's not needed.
Make tdc_remove_table() optionally acquire LOCK_open
to simplify usage of this function.
Use the right mutex in the partitioning code when
manipulating with thd->open_tables.
sql/sql_base.h:
Update signatures of changes functions.
sql/sql_insert.cc:
Do not wrap quick_rm_table() with LOCK_open acquisition,
this is unnecessary.
sql/sql_parse.cc:
Update to the new calling convention of tdc_remove_table().
Update to the new signature of close_cached_tables().
Update comments.
sql/sql_rename.cc:
Update to the new calling convention of tdc_remove_table().
Remove acquisition of LOCK_open around filesystem
operations.
sql/sql_show.cc:
Remove get_trigger_table_impl().
Do not acquire LOCK_open for a dirty read of the trigger
file.
sql/sql_table.cc:
Do not acquire LOCK_open for filesystem operations.
sql/sql_trigger.cc:
Do not require LOCK_open for trigger file I/O.
sql/sql_truncate.cc:
Update to the new signature of tdc_remove_table().
sql/sql_view.cc:
Do not require LOCK_open for view I/O.
Use tdc_remove_table() to expel view share.
Update comments.
sql/sys_vars.cc:
Update to the new signature of close_cached_tables().
Remove acquisition of LOCK_open around file system operations,
since such operations are now protected by metadata locks.
Rework table discovery algorithm to not require LOCK_open.
No new tests added since all MDL locking operations are covered
in lock.test and mdl_sync.test, and as long as these tests
pass despite the increased concurrency, consistency must be
unaffected.
sql/sql_base.cc:
Update a comment to not refer to a non-existing
function.
sql/sql_base.h:
Remove unused declarations (bad merge with the header
files split worklog).
sql/sql_test.cc:
Cleanup: remove unused declarations.
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).
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.
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().
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.
sporadically
There are two problems:
1. When closing temporary tables, during the THD clean up - and
after the session connection was already closed, there is a
chance we can push an error into the THD diagnostics area, if
the writing of the implicit DROP event to the binary log fails
for some reason. As a consequence an assertion can be
triggered, because at that point the diagnostics area is
already set.
2. Using push_warning with MYSQL_ERROR::WARN_LEVEL_ERROR is a
bug.
Given that close_temporary_tables is mostly called from
THD::cleanup - ie, with the session already closed, we fix
problem #1 by allowing the diagnostics area to be
overwritten. There is one other place in the code that calls
close_temporary_tables - while applying Start_log_event_v3. To
cover that case, we make close_temporary_tables to return the
error, thus, propagating upwards in the stack.
To fix problem #2, we replace push_warning with sql_print_error.
sql/log_event.cc:
Added handling of error returned by close_temporary_tables to
Start_log_event_v3::do_apply_event.
sql/sql_base.cc:
Three changes to close_temporary_tables:
1. it returns a boolean now (instead of void)
2. it uses sql_print_error instead of push_warning when writing to
binary log fails
3. we set can_overwrite_status before writing to the binary log,
thence not risking triggering an assertion by any other push
into diagnostics area happening inside mysql_bin_log.write.
sql/sql_base.h:
Changed the interface of close_temporary_tables so that it returns
bool instead of void.
sporadically
There are two problems:
1. When closing temporary tables, during the THD clean up - and
after the session connection was already closed, there is a
chance we can push an error into the THD diagnostics area, if
the writing of the implicit DROP event to the binary log fails
for some reason. As a consequence an assertion can be
triggered, because at that point the diagnostics area is
already set.
2. Using push_warning with MYSQL_ERROR::WARN_LEVEL_ERROR is a
bug.
Given that close_temporary_tables is mostly called from
THD::cleanup - ie, with the session already closed, we fix
problem #1 by allowing the diagnostics area to be
overwritten. There is one other place in the code that calls
close_temporary_tables - while applying Start_log_event_v3. To
cover that case, we make close_temporary_tables to return the
error, thus, propagating upwards in the stack.
To fix problem #2, we replace push_warning with sql_print_error.
DROP/ALTER/CREATE DATABASE with open HANDLER".
Remove wait_for_condition() which became unused after
database locks were replaced with MDL scoped locks.
If one needs functionality provided by this call one can
always use THD::enter_cond()/exit_cond() methods.
Also removed an unused include from sql_db.cc and updated
comment describing one of used includes to reflect current
situation.
DROP/ALTER/CREATE DATABASE with open HANDLER".
Remove wait_for_condition() which became unused after
database locks were replaced with MDL scoped locks.
If one needs functionality provided by this call one can
always use THD::enter_cond()/exit_cond() methods.
Also removed an unused include from sql_db.cc and updated
comment describing one of used includes to reflect current
situation.
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.
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.
an atomic counter"
Split the large LOCK_open section in open_table().
Do not call open_table_from_share() under LOCK_open.
Remove thd->version.
This fixes
Bug#50589 "Server hang on a query evaluated using a temporary
table"
Bug#51557 "LOCK_open and kernel_mutex are not happy together"
Bug#49463 "LOCK_table and innodb are not nice when handler
instances are created".
This patch has effect on storage engines that rely on
ha_open() PSEA method being called under LOCK_open.
In particular:
1) NDB is broken and left unfixed. NDB relies on LOCK_open
being kept as part of ha_open(), since it uses auto-discovery.
While previously the NDB open code was race-prone, now
it simply fails on asserts.
2) HEAP engine had a race in ha_heap::open() when
a share for the same table could be added twice
to the list of shares, or a dangling reference to a share
stored in HEAP handler. This patch aims to address this
problem by 'pinning' the newly created share in the
internal HEAP engine share list until at least one
handler instance is created using that share.
include/heap.h:
Add members to HP_CREATE_INFO.
Declare heap_release_share().
sql/lock.cc:
Remove thd->version, use thd->open_tables->s->version instead.
sql/repl_failsafe.cc:
Remove thd->version.
sql/sql_base.cc:
- close_thread_table(): move handler cleanup code outside the critical section protected by LOCK_open.
- remove thd->version
- split the large critical section in open_table() that
opens a new table from share and is protected by LOCK_open
into 2 critical sections, thus reducing the critical path.
- make check_if_table_exists() acquire LOCK_open internally.
- use thd->open_tables->s->version instead of thd->refresh_version to make sure that all tables in
thd->open_tables are in the same refresh series.
sql/sql_base.h:
Add declaration for check_if_table_exists().
sql/sql_class.cc:
Remove init_open_tables_state(), it's now equal to
reset_open_tables_state().
sql/sql_class.h:
Remove thd->version, THD::init_open_tables_state().
sql/sql_plugin.cc:
Use table->m_needs_reopen to mark the table as stale
rather than manipulate with thd->version, which is no more.
sql/sql_udf.cc:
Use table->m_needs_reopen to mark the table as stale
rather than manipulate with thd->version, which is no more.
sql/table.h:
Remove an unused variable.
sql/tztime.cc:
Use table->m_needs_reopen to mark the table as stale
rather than manipulate with thd->version, which is no more.
storage/heap/CMakeLists.txt:
Add heap tests to cmake build files.
storage/heap/ha_heap.cc:
Fix a race when ha_heap::ha_open() could insert two
HP_SHARE objects into the internal share list or store
a dangling reference to a share in ha_heap instance,
or wrongly set implicit_emptied.
storage/heap/hp_create.c:
Optionally pin a newly created share in the list of shares
by increasing its open_count. This is necessary to
make sure that a newly created share doesn't disappear while
a HP_INFO object is being created to reference it.
storage/heap/hp_open.c:
When adding a new HP_INFO object to the list of objects
in the heap share, make sure the open_count is not increased
twice.
storage/heap/hp_test1.c:
Adjust the test to new function signatures.
storage/heap/hp_test2.c:
Adjust the test to new function signatures.
an atomic counter"
Split the large LOCK_open section in open_table().
Do not call open_table_from_share() under LOCK_open.
Remove thd->version.
This fixes
Bug#50589 "Server hang on a query evaluated using a temporary
table"
Bug#51557 "LOCK_open and kernel_mutex are not happy together"
Bug#49463 "LOCK_table and innodb are not nice when handler
instances are created".
This patch has effect on storage engines that rely on
ha_open() PSEA method being called under LOCK_open.
In particular:
1) NDB is broken and left unfixed. NDB relies on LOCK_open
being kept as part of ha_open(), since it uses auto-discovery.
While previously the NDB open code was race-prone, now
it simply fails on asserts.
2) HEAP engine had a race in ha_heap::open() when
a share for the same table could be added twice
to the list of shares, or a dangling reference to a share
stored in HEAP handler. This patch aims to address this
problem by 'pinning' the newly created share in the
internal HEAP engine share list until at least one
handler instance is created using that share.
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.
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.
Conflicts:
Text conflict in mysql-test/r/archive.result
Contents conflict in mysql-test/r/innodb_bug38231.result
Text conflict in mysql-test/r/mdl_sync.result
Text conflict in mysql-test/suite/binlog/t/disabled.def
Text conflict in mysql-test/suite/rpl_ndb/r/rpl_ndb_binlog_format_errors.result
Text conflict in mysql-test/t/archive.test
Contents conflict in mysql-test/t/innodb_bug38231.test
Text conflict in mysql-test/t/mdl_sync.test
Text conflict in sql/sp_head.cc
Text conflict in sql/sql_show.cc
Text conflict in sql/table.cc
Text conflict in sql/table.h
Conflicts:
Text conflict in mysql-test/r/archive.result
Contents conflict in mysql-test/r/innodb_bug38231.result
Text conflict in mysql-test/r/mdl_sync.result
Text conflict in mysql-test/suite/binlog/t/disabled.def
Text conflict in mysql-test/suite/rpl_ndb/r/rpl_ndb_binlog_format_errors.result
Text conflict in mysql-test/t/archive.test
Contents conflict in mysql-test/t/innodb_bug38231.test
Text conflict in mysql-test/t/mdl_sync.test
Text conflict in sql/sp_head.cc
Text conflict in sql/sql_show.cc
Text conflict in sql/table.cc
Text conflict in sql/table.h
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().
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.
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).
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.