Bug#54678: InnoDB, TRUNCATE, ALTER, I_S SELECT, crash or deadlock
- Incompatible change: truncate no longer resorts to a row by
row delete if the storage engine does not support the truncate
method. Consequently, the count of affected rows does not, in
any case, reflect the actual number of rows.
- Incompatible change: it is no longer possible to truncate a
table that participates as a parent in a foreign key constraint,
unless it is a self-referencing constraint (both parent and child
are in the same table). To work around this incompatible change
and still be able to truncate such tables, disable foreign checks
with SET foreign_key_checks=0 before truncate. Alternatively, if
foreign key checks are necessary, please use a DELETE statement
without a WHERE condition.
Problem description:
The problem was that for storage engines that do not support
truncate table via a external drop and recreate, such as InnoDB
which implements truncate via a internal drop and recreate, the
delete_all_rows method could be invoked with a shared metadata
lock, causing problems if the engine needed exclusive access
to some internal metadata. This problem originated with the
fact that there is no truncate specific handler method, which
ended up leading to a abuse of the delete_all_rows method that
is primarily used for delete operations without a condition.
Solution:
The solution is to introduce a truncate handler method that is
invoked when the engine does not support truncation via a table
drop and recreate. This method is invoked under a exclusive
metadata lock, so that there is only a single instance of the
table when the method is invoked.
Also, the method is not invoked and a error is thrown if
the table is a parent in a non-self-referencing foreign key
relationship. This was necessary to avoid inconsistency as
some integrity checks are bypassed. This is inline with the
fact that truncate is primarily a DDL operation that was
designed to quickly remove all data from a table.
mysql-test/suite/innodb/t/innodb-truncate.test:
Add test cases for truncate and foreign key checks.
Also test that InnoDB resets auto-increment on truncate.
mysql-test/suite/innodb/t/innodb.test:
FK is not necessary, test is related to auto-increment.
Update error number, truncate is no longer invoked if
table is parent in a FK relationship.
mysql-test/suite/innodb/t/innodb_mysql.test:
Update error number, truncate is no longer invoked if
table is parent in a FK relationship.
Use delete instead of truncate, test is used to check
the interaction of FKs, triggers and delete.
mysql-test/suite/parts/inc/partition_check.inc:
Fix typo.
mysql-test/suite/sys_vars/t/foreign_key_checks_func.test:
Update error number, truncate is no longer invoked if
table is parent in a FK relationship.
mysql-test/t/mdl_sync.test:
Modify test case to reflect and ensure that truncate takes
a exclusive metadata lock.
mysql-test/t/trigger-trans.test:
Update error number, truncate is no longer invoked if
table is parent in a FK relationship.
sql/ha_partition.cc:
Reorganize the various truncate methods. delete_all_rows is now
passed directly to the underlying engines, so as truncate. The
code responsible for truncating individual partitions is moved
to ha_partition::truncate_partition, which is invoked when a
ALTER TABLE t1 TRUNCATE PARTITION p statement is executed.
Since the partition truncate no longer can be invoked via
delete, the bitmap operations are not necessary anymore. The
explicit reset of the auto-increment value is also removed
as the underlying engines are now responsible for reseting
the value.
sql/handler.cc:
Wire up the handler truncate method.
sql/handler.h:
Introduce and document the truncate handler method. It assumes
certain use cases of delete_all_rows.
Add method to retrieve the list of foreign keys referencing a
table. Method is used to avoid truncating tables that are
parent in a foreign key relationship.
sql/share/errmsg-utf8.txt:
Add error message for truncate and FK.
sql/sql_lex.h:
Introduce a flag so that the partition engine can detect when
a partition is being truncated. Used to give a special error.
sql/sql_parse.cc:
Function mysql_truncate_table no longer exists.
sql/sql_partition_admin.cc:
Implement the TRUNCATE PARTITION statement.
sql/sql_truncate.cc:
Change the truncate table implementation to use the new truncate
handler method and to not rely on row-by-row delete anymore.
The truncate handler method is always invoked with a exclusive
metadata lock. Also, it is no longer possible to truncate a
table that is parent in some non-self-referencing foreign key.
storage/archive/ha_archive.cc:
Rename method as the description indicates that in the future
this could be a truncate operation.
storage/blackhole/ha_blackhole.cc:
Implement truncate as no operation for the blackhole engine in
order to remain compatible with older releases.
storage/federated/ha_federated.cc:
Introduce truncate method that invokes delete_all_rows.
This is required to support partition truncate as this
form of truncate does not implement the drop and recreate
protocol.
storage/heap/ha_heap.cc:
Introduce truncate method that invokes delete_all_rows.
This is required to support partition truncate as this
form of truncate does not implement the drop and recreate
protocol.
storage/ibmdb2i/ha_ibmdb2i.cc:
Introduce truncate method that invokes delete_all_rows.
This is required to support partition truncate as this
form of truncate does not implement the drop and recreate
protocol.
storage/innobase/handler/ha_innodb.cc:
Rename delete_all_rows to truncate. InnoDB now does truncate
under a exclusive metadata lock.
Introduce and reorganize methods used to retrieve the list
of foreign keys referenced by a or referencing a table.
storage/myisammrg/ha_myisammrg.cc:
Introduce truncate method that invokes delete_all_rows.
This is required in order to remain compatible with earlier
releases where truncate would resort to a row-by-row delete.
Problem: CASE didn't work with a mixture of different character
sets in THEN/ELSE in some cases.
This happened because after character set aggregation
newly created Item_func_conv_charset items corresponding
to THEN/ELSE arguments were not put back to args[] array.
Fix:
put all Item_func_conv_charset back to args[].
@ mysql-test/include/ctype_numconv.inc
@ mysql-test/r/ctype_ucs.result
Adding tests
@ sql/item_cmpfunc.cc
Put "agg" back to args[] after character set aggregation.
thd->in_sub_stmt
In a precursor patch for Bug#52044
(revid:bzr/kostja@stripped), a
number of reorganizations of code was made. In addition some
assertions were added to ensure the correct transactional state.
The reorganization had a small glitch so statements that was
active in the query cache was not followed by a
statement commit/rollback (this code was removed). A section
in the trans_commit_stmt/trans_rollback_stmt code is to
clear the thd->transaction.stmt list of affected storage
engines. When a new statement is initiated, an assert
introduced by the 523044 patch checks if this list is cleared.
When the query cache is accessed, this list may be populated,
and since it's not committed it will not be cleared.
This fix adds explicit statement commit or rollback for
statements that is contained in the query cache.
for ALTER TABLE + MERGE tables
The patch for Bug#56292 changed how metadata locks are taken for MERGE
tables. After the patch, locking the MERGE table will also lock the
children tables with the same metadata lock type. This means that
LOCK TABLES on a MERGE table also will implicitly do LOCK TABLES on
the children tables.
A consequence of this change, is that it is possible to do LOCK TABLES
on a child table both explicitly and implicitly with the same statement
and that these two locks can be of different strength. For example,
LOCK TABLES child READ, merge WRITE.
In LOCK TABLES mode, we are not allowed to take new locks and each
statement must therefore try to find an existing TABLE instance with
a suitable lock. The code that searched for a suitable TABLE instance,
only considered table level locks. If a child table was locked twice,
it was therefore possible for this code to find a TABLE instance with
suitable table level locks but without suitable metadata lock.
This problem caused the assert in upgrade_shared_lock_to_exclusive()
to be triggered as it tried to upgrade a MDL_SHARED lock to
EXCLUSIVE. The problem was a regression caused by the patch for
Bug#56292.
This patch fixes the problem by partially reverting the changes
done by Bug#56292. Now, the children tables will only use the
same metadata lock as the MERGE table for MDL_SHARED_NO_WRITE
when not in locked tables mode. This means that LOCK TABLE
on a MERGE table will not implicitly lock the children tables.
This still fixes the original problem in Bug#56292 without
causing a regression.
Test case added to merge.test.
In case of failure in ALTER ... PARTITION under LOCK TABLE
the server could crash, due to it had modified the locked
table object, which was not reverted in case of failure,
resulting in a bad table definition used after the failed
command.
Solved by always closing the LOCKED TABLE, even in case
of error.
Note: this is a 5.1-only fix, bug#56172 fixed it in 5.5+
mysql-test/r/partition_innodb_plugin.result:
updated result
mysql-test/t/disabled.def:
Only disabled valgrind instead.
mysql-test/t/partition_innodb_plugin.test:
Added test
sql/sql_partition.cc:
close_thread_tables do not close LOCKED TABLEs
and destroys the table object (including part_info),
so to avoid it to be reused, always close the table
regardless of any previous failure.
This assert was triggered if DELETE was done on a view that
referenced another view which in turn (directly or indirectly)
referenced more than one table.
Delete from a view referencing more than one table (a join view)
is not supported and is supposed to give ER_VIEW_DELETE_MERGE_VIEW
error. Before this error was reported from the multi table
delete code, an assert verified that the view from the DELETE statement
had more than one underlying table. However, this assert did not take
into account that the view could refer to another view which in turn
referenced the actual tables.
This patch fixes the problem by adjusting the assert to take this
possibility into account. This problem was only noticeable on debug
builds of the server. On release builds, ER_VIEW_DELETE_MERGE_VIEW
was correctly reported.
Test case added to delete.test.
LOAD DATA into partitioned MyISAM table
Problem was that both partitioning and myisam
used the same table_share->mutex for different protections
(auto inc and repair).
Solved by adding a specific mutex for the partitioning
auto_increment.
Also adding destroying the ha_data structure in
free_table_share (which is to be propagated
into 5.5).
This is a 5.1 ONLY patch, already fixed in 5.5+.
The crash happens because original join table is replaced with temporary table
at execution stage and later we attempt to use this temporary table in
select_describe. It might happen that
Item_subselect::update_used_tables() method which sets const_item flag
is not called by some reasons (no where/having conditon in subquery for example).
It prevents JOIN::join_tmp creation and breaks original join.
The fix is to call ::update_used_tables() before ::const_item() check.
mysql-test/r/ps.result:
test case
mysql-test/t/ps.test:
test case
sql/item_subselect.cc:
call ::update_used_tables() before ::const_item() check.
Bug#57113: ha_partition::extra(ha_extra_function):
Assertion `m_extra_cache' failed
Fix for bug#55458 included DBUG_ASSERTS causing
debug builds of the server to crash on
another multi-table update.
Removed the asserts since they where wrong.
(updated after testing the patch in 5.5).
mysql-test/r/partition.result:
updated result
mysql-test/t/partition.test:
Added test for bug#57113
sql/ha_partition.cc:
Removed the assert for m_extra_cache when
::extra(HA_PREPARE_FOR_UPDATE) was called.
This crash occured if the same debug trace file was closed twice,
leading to the same memory being free'd twice. This could occur
if the "debug" server system variable refered to the same trace
file in both global and session scope.
Example of an order of events that would lead to a crash:
1) Enable debug tracing to a trace file (global scope)
2) Enable debug tracing to the same trace file (session scope)
3) Reset debug settings (global scope)
4) Reset debug settings (session scope)
This caused a crash because the trace file was, by mistake, closed
in 3), leading to the same memory being free'd twice when the file
was closed again in 4).
Internally, the debug settings are stored in a stack, with session
settings (if any) on top and the global settings below. Each connection
has its own stack. When a set of settings is changed, it must be
determined if its debug trace file is to be closed. Before, this was done
by only checking below on the settings stack. So if the global settings
were changed, an existing debug trace file reference in session settings
would be missed. This caused the file to be closed even if it was in use,
leading to a crash later when it was closed again.
This patch fixes the problem by preventing the trace file from being shared
between global and session settings. If session debug settings are set without
specifying a new trace file, stderr is used for output. This is a change
in behaviour and should be reflected in the documentation.
Test case added to variables.test.
This patch implements I_S.PLUGINS.LOAD_OPTION column
as specified by WL#5496.
mysql-test/r/plugin_load_option.result:
A test case for WL#5496.
mysql-test/suite/funcs_1/r/is_columns_is.result:
Adjusted a test case according to WL#5496.
mysql-test/t/plugin_load_option.test:
A test case for WL#5496.
sql/sql_show.cc:
Added LOAD_OPTION column to I_S.PLUGINS.
This patch implements "permanent" load option for
plugins as specified by WL#5341.
mysql-test/r/plugin_load_option.result:
A test case for WL#5341.
mysql-test/t/plugin_load_option-master.opt:
A test case for WL#5341.
mysql-test/t/plugin_load_option.test:
A test case for WL#5341.
sql/share/errmsg-utf8.txt:
An error message for WL#5341.
sql/sql_plugin.cc:
Added FORCE_PLUS_PERMANENT plugin load option.
sql/sql_plugin.h:
Expose and use plugin load option instead of
is_mandatory flag. This is a requirement for
to-be-implemented WL5496.
but broken.
Before this patch, it was allowed to use stored functions in
HANDLER ... READ statements. The problem was that this functionality
was not really supported by the code. Proper locking would for example
not be performed, and it was also possible to break replication by
having stored functions that performed updates.
This patch disallows the use of stored functions in HANDLER ... READ.
Any such statement will now give an ER_NOT_SUPPORTED_YET error.
This is an incompatible change and should be reflected in the
documentation.
Test case added to handler_myisam/handler_innodb.test.
