+ failing statements
Implicit DROP event for temporary table is not getting
LOG_EVENT_THREAD_SPECIFIC_F flag, because, in the previous
executed statement in the same thread, which might even be a
failed statement, the thread_specific_used flag is set to
FALSE (in mysql_reset_thd_for_next_command) and not set to TRUE
before connection is shutdown. This means that implicit DROP
event will take the FALSE value from thread_specific_used and
will not set LOG_EVENT_THREAD_SPECIFIC_F in the event header. As
a consequence, mysqlbinlog will not print the pseudo_thread_id
from the DROP event, because one of the requirements for the
printout is that this flag is set to TRUE.
We fix this by setting thread_specific_used whenever we are
binlogging a DROP in close_temporary_tables, and resetting it to
its previous value afterward.
+ failing statements
Implicit DROP event for temporary table is not getting
LOG_EVENT_THREAD_SPECIFIC_F flag, because, in the previous
executed statement in the same thread, which might even be a
failed statement, the thread_specific_used flag is set to
FALSE (in mysql_reset_thd_for_next_command) and not set to TRUE
before connection is shutdown. This means that implicit DROP
event will take the FALSE value from thread_specific_used and
will not set LOG_EVENT_THREAD_SPECIFIC_F in the event header. As
a consequence, mysqlbinlog will not print the pseudo_thread_id
from the DROP event, because one of the requirements for the
printout is that this flag is set to TRUE.
We fix this by setting thread_specific_used whenever we are
binlogging a DROP in close_temporary_tables, and resetting it to
its previous value afterward.
The problem was that ALTER TABLE on a merge table which was locked
using LOCK TABLE ... WRITE, by mistake gave
ER_TABLE_NOT_LOCKED_FOR_WRITE.
During opening of the table to be ALTERed, open_table() tried to
get an upgradable metadata lock. In LOCK TABLEs mode, this lock
must already exist (i.e. taken by LOCK TABLE) as new locks of this
type cannot be acquired for fear of deadlock. So in LOCK TABLEs
mode, open_table() tried to find an existing upgradable lock for
the table to be altered.
The problem was that open_table() also tried to find upgradable
metadata locks for children of merge tables even if no such
locks are needed to execute ALTER TABLE on merge tables.
This patch fixes the problem by making sure that open tables code
only searches for upgradable metadata locks for the merge table
and not for the merge children tables.
The patch also fixes a related bug where an upgradable metadata
lock was aquired outside of LOCK TABLEs mode even if the table in
question was temporary. This bug meant that LOCK TABLES or DDL on
temporary tables by mistake could be blocked/aborted by locks held
on base tables with the same table name by other connections.
Test cases added to merge.test and lock_multi.test.
The problem was that ALTER TABLE on a merge table which was locked
using LOCK TABLE ... WRITE, by mistake gave
ER_TABLE_NOT_LOCKED_FOR_WRITE.
During opening of the table to be ALTERed, open_table() tried to
get an upgradable metadata lock. In LOCK TABLEs mode, this lock
must already exist (i.e. taken by LOCK TABLE) as new locks of this
type cannot be acquired for fear of deadlock. So in LOCK TABLEs
mode, open_table() tried to find an existing upgradable lock for
the table to be altered.
The problem was that open_table() also tried to find upgradable
metadata locks for children of merge tables even if no such
locks are needed to execute ALTER TABLE on merge tables.
This patch fixes the problem by making sure that open tables code
only searches for upgradable metadata locks for the merge table
and not for the merge children tables.
The patch also fixes a related bug where an upgradable metadata
lock was aquired outside of LOCK TABLEs mode even if the table in
question was temporary. This bug meant that LOCK TABLES or DDL on
temporary tables by mistake could be blocked/aborted by locks held
on base tables with the same table name by other connections.
Test cases added to merge.test and lock_multi.test.
This patch prevents system threads and system table accesses from
using user-specified values for "lock_wait_timeout". Instead all
such accesses are done using the default value (1 year).
This prevents background tasks (such as replication, events,
accessing stored function definitions, logging, reading time-zone
information, etc.) from failing in cases where the global value
of "lock_wait_timeout" is set very low.
The patch also simplifies the open tables API. Rather than adding
another convenience function for opening and locking system tables,
this patch removes most of the existing convenience functions for
open_and_lock_tables_derived(). Before, open_and_lock_tables() was
a convenience function that enforced derived tables handling, while
open_and_lock_tables_derived() was the main function where derived
tables handling was optional. Now, this convencience function is
gone and the main function is renamed to open_and_lock_tables().
No test case added as it would have required the use of --sleep to
check that system threads and system tables have a different timeout
value from the user-specified "lock_wait_timeout" system variable.
This patch prevents system threads and system table accesses from
using user-specified values for "lock_wait_timeout". Instead all
such accesses are done using the default value (1 year).
This prevents background tasks (such as replication, events,
accessing stored function definitions, logging, reading time-zone
information, etc.) from failing in cases where the global value
of "lock_wait_timeout" is set very low.
The patch also simplifies the open tables API. Rather than adding
another convenience function for opening and locking system tables,
this patch removes most of the existing convenience functions for
open_and_lock_tables_derived(). Before, open_and_lock_tables() was
a convenience function that enforced derived tables handling, while
open_and_lock_tables_derived() was the main function where derived
tables handling was optional. Now, this convencience function is
gone and the main function is renamed to open_and_lock_tables().
No test case added as it would have required the use of --sleep to
check that system threads and system tables have a different timeout
value from the user-specified "lock_wait_timeout" system variable.
- Avoid full inline of mark_trx_read_write() for many functions
- Avoid somewhat expensive tests for every write/update/delete row
sql/handler.h:
Adde ha_start_of_new_statement() to reset internal variables as part of the code in "open_table" that resets TABLE object for the new statement
Faster mark_trx_read_write_part()
sql/sql_base.cc:
Don't manipulate table->file internal structs directly
an INFORMATION_SCHEMA table
When a prepared statement using a merged view containing an information
schema table was executed, a metadata lock of the view was not taken.
This meant that it was possible for concurrent view DDL to execute,
thereby breaking the binary log. For example, it was possible
for DROP VIEW to appear in the binary log before a query using the view.
This also happened when a statement in a stored routine was executed a
second time.
For such views, the information schema table is merged into the view
during the prepare phase (or first execution of a statement in a routine).
The problem was that we took a short cut and were not executing full-blown
view opening during subsequent executions of the statement. As a result,
a metadata lock on the view was not taken to protect the view definition.
This patch resolves the problem by making sure a metadata lock is taken
for views even after information schema tables are merged into them.
Test cased added to view.test.
an INFORMATION_SCHEMA table
When a prepared statement using a merged view containing an information
schema table was executed, a metadata lock of the view was not taken.
This meant that it was possible for concurrent view DDL to execute,
thereby breaking the binary log. For example, it was possible
for DROP VIEW to appear in the binary log before a query using the view.
This also happened when a statement in a stored routine was executed a
second time.
For such views, the information schema table is merged into the view
during the prepare phase (or first execution of a statement in a routine).
The problem was that we took a short cut and were not executing full-blown
view opening during subsequent executions of the statement. As a result,
a metadata lock on the view was not taken to protect the view definition.
This patch resolves the problem by making sure a metadata lock is taken
for views even after information schema tables are merged into them.
Test cased added to view.test.
This patch introduces timeouts for metadata locks.
The timeout is specified in seconds using the new dynamic system
variable "lock_wait_timeout" which has both GLOBAL and SESSION
scopes. Allowed values range from 1 to 31536000 seconds (= 1 year).
The default value is 1 year.
The new server parameter "lock-wait-timeout" can be used to set
the default value parameter upon server startup.
"lock_wait_timeout" applies to all statements that use metadata locks.
These include DML and DDL operations on tables, views, stored procedures
and stored functions. They also include LOCK TABLES, FLUSH TABLES WITH
READ LOCK and HANDLER statements.
The patch also changes thr_lock.c code (table data locks used by MyISAM
and other simplistic engines) to use the same system variable.
InnoDB row locks are unaffected.
One exception to the handling of the "lock_wait_timeout" variable
is delayed inserts. All delayed inserts are executed with a timeout
of 1 year regardless of the setting for the global variable. As the
connection issuing the delayed insert gets no notification of
delayed insert timeouts, we want to avoid unnecessary timeouts.
It's important to note that the timeout value is used for each lock
acquired and that one statement can take more than one lock.
A statement can therefore block for longer than the lock_wait_timeout
value before reporting a timeout error. When lock timeout occurs,
ER_LOCK_WAIT_TIMEOUT is reported.
Test case added to lock_multi.test.
include/my_pthread.h:
Added macros for comparing two timespec structs.
include/thr_lock.h:
Introduced timeouts for thr_lock.c locks.
mysql-test/r/mysqld--help-notwin.result:
Updated result file with the new server variable.
mysql-test/r/mysqld--help-win.result:
Updated result file with the new server variable.
mysql-test/suite/sys_vars/r/lock_wait_timeout_basic.result:
Added basic test for the new server variable.
mysql-test/suite/sys_vars/t/lock_wait_timeout_basic.test:
Added basic test for the new server variable.
mysys/thr_lock.c:
Introduced timeouts for thr_lock.c locks.
sql/mdl.cc:
Introduced timeouts for metadata locks.
sql/mdl.h:
Introduced timeouts for metadata locks.
sql/sql_base.cc:
Introduced timeouts in tdc_wait_for_old_versions().
sql/sql_class.h:
Added new server variable lock_wait_timeout.
sql/sys_vars.cc:
Added new server variable lock_wait_timeout.
This patch introduces timeouts for metadata locks.
The timeout is specified in seconds using the new dynamic system
variable "lock_wait_timeout" which has both GLOBAL and SESSION
scopes. Allowed values range from 1 to 31536000 seconds (= 1 year).
The default value is 1 year.
The new server parameter "lock-wait-timeout" can be used to set
the default value parameter upon server startup.
"lock_wait_timeout" applies to all statements that use metadata locks.
These include DML and DDL operations on tables, views, stored procedures
and stored functions. They also include LOCK TABLES, FLUSH TABLES WITH
READ LOCK and HANDLER statements.
The patch also changes thr_lock.c code (table data locks used by MyISAM
and other simplistic engines) to use the same system variable.
InnoDB row locks are unaffected.
One exception to the handling of the "lock_wait_timeout" variable
is delayed inserts. All delayed inserts are executed with a timeout
of 1 year regardless of the setting for the global variable. As the
connection issuing the delayed insert gets no notification of
delayed insert timeouts, we want to avoid unnecessary timeouts.
It's important to note that the timeout value is used for each lock
acquired and that one statement can take more than one lock.
A statement can therefore block for longer than the lock_wait_timeout
value before reporting a timeout error. When lock timeout occurs,
ER_LOCK_WAIT_TIMEOUT is reported.
Test case added to lock_multi.test.
A closely related problem, hardly worth a new bug report:
Removed a spurious call to:
thd->set_current_stmt_binlog_format_row_if_mixed()
in sql_base.cc:lock_tables().
A closely related problem, hardly worth a new bug report:
Removed a spurious call to:
thd->set_current_stmt_binlog_format_row_if_mixed()
in sql_base.cc:lock_tables().
myisam-recover options changed from OFF to 'DEFAULT' to get less change of data loss when using MyISAM.
(The disadvantage is that changed MyISAM tables will be checked at access time; Use --myisam-recover=OFF for old behavior)
Don't call extra(HA_EXTRA_FORCE_REOPEN) in ALTER TABLE if table is locked as this will mark table as crashed!
Added assert to detect if we accidently would use MyISAM versioning in MySQL
include/my_base.h:
Mark NOT_USED as USED, as we now use this as a flag to not call extra()
mysql-test/mysql-test-run.pl:
Don't write all options when there is something wrong with the arguments
mysql-test/r/sp-destruct.result:
Add missing flush of mysql.proc (as the test copied live tables)
mysql-test/r/variables.result:
myisam-recover options changed to 'default'
mysql-test/r/view.result:
Don't show create time in result
mysql-test/suite/maria/t/maria-recovery2-master.opt:
Don't run test with myisam-recover (as this produces extra warnings during simulated death)
mysql-test/t/sp-destruct.test:
Add missing flush of mysql.proc (as the test copied live tables)
mysql-test/t/view.test:
Don't show create time in result
sql/lock.cc:
Added marker if table was deleted to argument list
sql/mysql_priv.h:
Added marker if table was deleted to argument list
sql/mysqld.cc:
myisam-recover options changed from OFF to 'DEFAULT' to get less change of data loss when using MyISAM
Allow one to specify OFF as argument to myisam-recover (was default before but one couldn't specify it)
sql/sql_base.cc:
Mark if table is going to be deleted
sql/sql_delete.cc:
Mark if table is going to be deleted
sql/sql_table.cc:
Mark if table is going to be deleted
Don't call extra(HA_EXTRA_FORCE_REOPEN) in ALTER TABLE if table is locked as this will mark table as crashed!
sql/table.cc:
Signal to handler if table is getting deleted as part of getting droped from table cache.
sql/table.h:
Added marker if table is going to be deleted.
storage/maria/ha_maria.cc:
Don't search for transaction handler if file is not transactional or outside of transaction
(Fixed possible core dump)
storage/maria/ma_blockrec.c:
Don't write changed information if table is going to be deleted.
storage/maria/ma_close.c:
Don't write changed information if table is going to be deleted.
storage/maria/ma_extra.c:
Mark tables that are deleted as crased, to ensure good behavior on restart if we suddenly crash.
storage/maria/ma_locking.c:
Cleanup
storage/maria/ma_recovery.c:
We need trnman to be inited during redo phase (to be able to open tables checked with maria_chk)
storage/maria/maria_def.h:
Added marker if table is going to be deleted.
storage/myisam/mi_close.c:
Don't write changed information if table is going to be deleted.
storage/myisam/mi_extra.c:
Mark tables that are deleted as crased, to ensure good behavior on restart if we suddenly crash.
storage/myisam/mi_open.c:
Added assert to detect if we accidently would use MyISAM versioning in MySQL
storage/myisam/myisamdef.h:
Added marker if table is going to be deleted.
and MDL".
Concurrent execution of a multi-DELETE statement and ALTER
TABLE statement which affected one of the tables used in
the multi-DELETE sometimes led to deadlock.
Similar deadlocks might have occured when one performed
INSERT/UPDATE/DELETE on a view and concurrently executed
ALTER TABLE for the view's underlying table, or when one
concurrently executed TRUNCATE TABLE for InnoDB table and
ALTER TABLE for the same table.
These deadlocks were caused by a discrepancy between types of
metadata and thr_lock.cc locks acquired by those statements.
What happened was that multi-DELETE/TRUNCATE/DML-through-the-
view statement in the first connection acquired SR lock on a
table, then ALTER TABLE would come in in the second connection
and acquire SNW metadata lock and TL_WRITE_ALLOW_READ
thr_lock.c lock and then would start waiting for the first
connection during lock upgrade. After that the statement in
the first connection would try to acquire TL_WRITE lock on
table and would start waiting for the second connection,
creating a deadlock.
This patch solves this problem by ensuring that we acquire
SW metadata lock in all cases in which we acquiring write
thr_lock.c lock. This guarantees that deadlocks like the
one described above won't occur since all lock conflicts
in such situation are resolved within MDL subsystem.
This patch also adds assert which should guarantee that
such situations won't arise in future.
mysql-test/r/lock_multi.result:
Added main test for bug #50913 "Deadlock between
open_and_lock_tables_derived and MDL".
mysql-test/r/mdl_sync.result:
Added additional coverage for bug #50913 "Deadlock
between open_and_lock_tables_derived and MDL".
mysql-test/t/lock_multi.test:
Added main test for bug #50913 "Deadlock between
open_and_lock_tables_derived and MDL".
mysql-test/t/mdl_sync.test:
Added additional coverage for bug #50913 "Deadlock
between open_and_lock_tables_derived and MDL".
sql/lock.cc:
Added assert that enforces that when we are locking
a non-temporary table we have an appropriate type of
metadata lock on this table.
sql/mysql_priv.h:
Added separate flag for open_tables() to be able specify that
SH metadata locks on table to be open should be acquired.
We can no longer use MYSQL_LOCK_IGNORE_FLUSH flag for this
as in addition to use in I_S implementation it is also used
for opening system tables. Since in the latter case we also
acquire thr_lock.c locks using SH metadata lock in it instead
of SR or SW locks may lead to deadlock.
sql/sql_base.cc:
When opening tables don't interpret MYSQL_LOCK_IGNORE_FLUSH
flag as request to acquire SH metadata locks. This flag is
also used for opening system tables for which we also take
thr_lock.c locks and thus proper metadata lock to take in
this case is SR or SW lock (otherwise deadlocks can occur).
In cases when SH lock is really required (e.g. when tables
are open by I_S implementation) we rely on that newly
introduced MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL flag is
used.
sql/sql_delete.cc:
mysql_truncate_by_delete():
Adjust type of metadata lock to be requested after changing
type of thr_lock.c lock for table list element from one
which was set in parser to TL_WRITE.
This removes discrepancy between types of these locks which
allowed deadlocks to creep in.
sql/sql_handler.cc:
When closing table which was open by HANDLER statement clear
TABLE::open_by_handler flag. This allows to use this flag as
a reliable indication that TABLE instance was open by HANDLER
statement in assert which was added to mysql_lock_tables().
sql/sql_parse.cc:
multi_delete_set_locks_and_link_aux_tables():
Adjust type of metadata lock to be requested after changing
type of thr_lock.c lock for table list element from one
which was set in parser to TL_WRITE.
This removes discrepancy between types of these locks which
allowed deadlocks to creep in.
sql/sql_show.cc:
Use newly introduced MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL
flag in order to acquire SH metadata locks when opening tables
in I_S implementation.
sql/sql_update.cc:
Added comment explaining why in multi-update after deciding
that we need weaker thr_lock.c lock on a table we don't
downgrade metadata lock on it.
sql/sql_view.cc:
When merging view into main statement adjust type of metadata
lock to be requested after changing type of thr_lock.c lock
for table. This removes discrepancy between types of these
locks which allowed deadlocks to creep in.
and MDL".
Concurrent execution of a multi-DELETE statement and ALTER
TABLE statement which affected one of the tables used in
the multi-DELETE sometimes led to deadlock.
Similar deadlocks might have occured when one performed
INSERT/UPDATE/DELETE on a view and concurrently executed
ALTER TABLE for the view's underlying table, or when one
concurrently executed TRUNCATE TABLE for InnoDB table and
ALTER TABLE for the same table.
These deadlocks were caused by a discrepancy between types of
metadata and thr_lock.cc locks acquired by those statements.
What happened was that multi-DELETE/TRUNCATE/DML-through-the-
view statement in the first connection acquired SR lock on a
table, then ALTER TABLE would come in in the second connection
and acquire SNW metadata lock and TL_WRITE_ALLOW_READ
thr_lock.c lock and then would start waiting for the first
connection during lock upgrade. After that the statement in
the first connection would try to acquire TL_WRITE lock on
table and would start waiting for the second connection,
creating a deadlock.
This patch solves this problem by ensuring that we acquire
SW metadata lock in all cases in which we acquiring write
thr_lock.c lock. This guarantees that deadlocks like the
one described above won't occur since all lock conflicts
in such situation are resolved within MDL subsystem.
This patch also adds assert which should guarantee that
such situations won't arise in future.
Cherry-pick a fix Bug#37148 from next-mr, to preserve
file ids of the added files, and ensure that all the necessary
changes have been pulled.
Since initially Bug#37148 was null-merged into 6.0,
the changeset that is now being cherry-picked was likewise
null merged into next-4284.
Now that Bug#37148 has been reapplied to 6.0, try to make
it work with next-4284. This is also necessary to be able
to pull other changes from 5.1-rep into next-4284.
To resolve the merge issues use this changeset applied
to 6.0:
revid:jperkin@sun.com-20091216103628-ylhqf7s6yegui2t9
revno: 3776.1.1
committer: He Zhenxing <zhenxing.he@sun.com>
branch nick: 6.0-codebase-bugfixing
timestamp: Thu 2009-12-17 17:02:50 +0800
message:
Fix merge problem with Bug#37148
Cherry-pick a fix Bug#37148 from next-mr, to preserve
file ids of the added files, and ensure that all the necessary
changes have been pulled.
Since initially Bug#37148 was null-merged into 6.0,
the changeset that is now being cherry-picked was likewise
null merged into next-4284.
Now that Bug#37148 has been reapplied to 6.0, try to make
it work with next-4284. This is also necessary to be able
to pull other changes from 5.1-rep into next-4284.
To resolve the merge issues use this changeset applied
to 6.0:
revid:jperkin@sun.com-20091216103628-ylhqf7s6yegui2t9
revno: 3776.1.1
committer: He Zhenxing <zhenxing.he@sun.com>
branch nick: 6.0-codebase-bugfixing
timestamp: Thu 2009-12-17 17:02:50 +0800
message:
Fix merge problem with Bug#37148
failed in open_ltable()
The problem was too restrictive asserts that enforced that
open_ltable() was called without any active HANDLERs, LOCK TABLES
or global read locks.
However, this can happen in several cases when opening system
tables. The assert would, for example, be triggered when drop
function was called from a connection with active HANDLERs as
this would cause open_ltable() to be called for mysql.proc.
The assert could also be triggered when using table-based
general log (mysql.general_log).
This patch removes the asserts since they will be triggered in
several legitimate cases and because the asserts are no longer
relevant due to changes in how locks are released.
The patch also fixes set_needs_thr_lock_abort() that before
ignored its parameter and always set the member variable to TRUE.
Test case added to mdl_sync.test.
Thanks to Dmitry Lenev for help with this bug!
failed in open_ltable()
The problem was too restrictive asserts that enforced that
open_ltable() was called without any active HANDLERs, LOCK TABLES
or global read locks.
However, this can happen in several cases when opening system
tables. The assert would, for example, be triggered when drop
function was called from a connection with active HANDLERs as
this would cause open_ltable() to be called for mysql.proc.
The assert could also be triggered when using table-based
general log (mysql.general_log).
This patch removes the asserts since they will be triggered in
several legitimate cases and because the asserts are no longer
relevant due to changes in how locks are released.
The patch also fixes set_needs_thr_lock_abort() that before
ignored its parameter and always set the member variable to TRUE.
Test case added to mdl_sync.test.
Thanks to Dmitry Lenev for help with this bug!
There was two problems:
The first was the symptom, caused by bad error handling in
ha_partition. It did not handle print_error etc. when
having no partitions (when used by dummy handler).
The second was the real problem that when dropping tables
it reused the table type (storage engine) from when the lock
was asked for, not the table type that it had when gaining
the exclusive name lock. So that it tried to delete tables
from wrong storage engines.
Solutions for the first problem was to accept some handler
calls to the partitioning handler even if it was not setup
with any partitions, and also if possible fallback
to use the base handler's default functions.
Solution for the second problem was to remove the optimization
to reuse the definition from the cache, instead always check
the frm-file when holding the LOCK_open mutex
(updated with a fix for a debug print crash and better
comments as required by reviewer, and removed optimization
to avoid reading the frm-file).
mysql-test/r/partition_debug_sync.result:
Bug#42438: Crash ha_partition::change_table_ptr
New result file using DEBUG_SYNC for deterministic results.
mysql-test/t/partition_debug_sync.test:
Bug#42438: Crash ha_partition::change_table_ptr
New test file using DEBUG_SYNC for deterministic results.
sql/ha_partition.cc:
Bug#42438: Crash ha_partition::change_table_ptr
allow some handler calls, used by error handling, even when
no partitions are setup. Fallback to default handling if possible.
sql/sql_base.cc:
Bug#42438: Crash ha_partition::change_table_ptr
Added DEBUG_SYNC point for deterministic test cases.
sql/sql_table.cc:
Bug#42438: Crash ha_partition::change_table_ptr
Always use the table type written in the .frm-file
(i.e. the current table type) when deleting a table.
Moved the check for log-table to not depend of the cache.
Added DEBUG_SYNC points for deterministic test cases.
