The problem was that TRUNCATE TABLE didn't take a exclusive
lock on a table if it resorted to truncating via delete of
all rows in the table. Specifically for InnoDB tables, this
could break proper isolation as InnoDB ends up aborting some
granted locks when truncating a table.
The solution is to take a exclusive metadata lock before
TRUNCATE TABLE can proceed. This guarantees that no other
transaction is using the table.
Incompatible change: Truncate via delete no longer fails
if sql_safe_updates is activated (this was a undocumented
side effect).
libmysqld/CMakeLists.txt:
Add new files to the build list.
libmysqld/Makefile.am:
Add new files to the build list.
mysql-test/extra/binlog_tests/binlog_truncate.test:
Add test case for Bug#42643
mysql-test/include/mix1.inc:
Update test case as TRUNCATE TABLE now grabs a exclusive lock.
Ensure that TRUNCATE waits for granted locks on the table.
mysql-test/suite/binlog/t/binlog_truncate_innodb.test:
As with other data modifying statements, TRUNCATE is still not
possible in a transaction with isolation level READ COMMITTED
or READ UNCOMMITED. It would be possible to implement so, but
it is not worth the effort.
mysql-test/suite/binlog/t/binlog_truncate_myisam.test:
Test under different binlog formats.
mysql-test/suite/binlog/t/disabled.def:
Re-enable test case.
mysql-test/t/innodb_bug38231.test:
Truncate no longer works with row-level locks.
mysql-test/t/mdl_sync.test:
Ensure that a acquired lock is not given up due to a conflict.
mysql-test/t/partition_innodb_semi_consistent.test:
End transaction as to release metadata locks.
mysql-test/t/truncate.test:
A metadata lock is now taken before the object is verified.
sql/CMakeLists.txt:
Add new files to the build list.
sql/Makefile.am:
Add new files to the build list.
sql/datadict.cc:
Introduce a new file specific for data dictionary operations.
sql/datadict.h:
Add header file.
sql/sql_base.cc:
Rename data dictionary function.
sql/sql_bitmap.h:
Include dependency.
sql/sql_delete.cc:
Move away from relying on mysql_delete() to delete all rows of
a table. Thus, move any bits related to truncate to sql_truncate.cc
sql/sql_delete.h:
Remove parameter.
sql/sql_parse.cc:
Add protection against the global read lock -- a intention
exclusive lock can be acquired in the truncate path.
sql/sql_show.cc:
Add sync point for testing scenarios where a pending flush
is ignored.
sql/sql_truncate.cc:
Acquire a shared metadata lock before accessing table metadata.
Upgrade the lock to a exclusive one if the table can be re-created.
Rework binlog rules to better reflect the requirements.
sql/sql_yacc.yy:
Set appropriate lock types for table to be truncated.
sql/table.h:
Move to data dictionary header.
TRUNCATE TABLE fails to replicate when stmt-based binlogging is not supported.
There were two separate problems with the code, both of which are fixed with
this patch:
1. An error was printed by InnoDB for TRUNCATE TABLE in statement mode when
the in isolation levels READ COMMITTED and READ UNCOMMITTED since InnoDB
does permit statement-based replication for DML statements. However,
the TRUNCATE TABLE is not transactional, but is a DDL, and should therefore
be allowed to be replicated as a statement.
2. The statement was not logged in mixed mode because of the error above, but
the error was not reported to the client.
This patch fixes the problem by treating TRUNCATE TABLE a DDL, that is, it is
always logged as a statement and not reporting an error from InnoDB for TRUNCATE
TABLE.
mysql-test/extra/binlog_tests/binlog_truncate.test:
Adding new test to check that TRUNCATE TABLE is written correctly
to the binary log.
mysql-test/extra/rpl_tests/rpl_truncate.test:
Removing redundant testing by eliminating settings of BINLOG_FORMAT.
mysql-test/extra/rpl_tests/rpl_truncate_helper.test:
Replacing slave and master reset code with include file.
Removing settings of BINLOG_FORMAT.
Replacing printing of table contents to compare master and slave
with diff_tables.inc.
mysql-test/suite/binlog/t/binlog_truncate_innodb.test:
Adding test for testing that TRUNCATE TABLE is logged correctly for InnoDB
in all isolation levels.
mysql-test/suite/binlog/t/binlog_truncate_myisam.test:
Adding test for testing that TRUNCATE TABLE is logged correctly for MyISAM.
mysql-test/suite/binlog/t/disabled.def:
Disabling binlog_truncate_innodb since it does not work (yet).
sql/sql_base.cc:
Correcting setting of capabilities flags to make the comparison with 0
later in the code work correctly.
sql/sql_delete.cc:
Re-organizing code to ensure that TRUNCATE TABLE is logged in statement
format and that row format is not used unless there are rows to log (which
there are not when delete_all_rows() is called, so this has to be logged
as a statement).
