truncating a temporary table
TRUNCATE expects only one TABLE instance (which is used by TRUNCATE
itself) to be open. However this requirement wasn't enforced after
"MDEV-5535: Cannot reopen temporary table".
Fixed by closing unused table instances before performing TRUNCATE.
This was caused by a combination of factors:
* MyISAM/Aria temporary tables historically never saved the state
to disk (MYI/MAI), because the state never needed to persist
* certain ALTER TABLE operations modify the original TABLE structure
and if they fail, the original table has to be reopened to
revert all changes (m_needs_reopen=1)
as a result, when ALTER fails and MyISAM/Aria temp table gets reopened,
it reads the stale state from the disk.
As a fix, MyISAM/Aria tables now *always* write the state to disk
on close, *unless* HA_EXTRA_PREPARE_FOR_DROP was done first. And
the server now always does HA_EXTRA_PREPARE_FOR_DROP before dropping
a temporary table.
THD::close_temporary_tables(): Revert the change.
ha_innobase::delete_table(): Move the work-around inside
a debug assertion, and check thd_kill_level() instead of thd_killed(),
because the latter would not hold for KILL_CONNECTION.
THD::close_temporary_tables(): Assign lex->sql_command so that
the debug assertion will not fail in ha_innobase::delete_table().
Alternatively, we could ensure that thd_killed() holds inside
ha_innobase::delete_table().
There should be no impact for the non-debug build. The thd_sql_command()
inside ha_innobase::delete_table() only affects the treatment of
persistent FOREIGN KEY metadata. There is no persistent metadata
nor foreign key constraints for temporary tables.
No test case was added, because the failure is nondeterministic.
- Fix win64 pointer truncation warnings
(usually coming from misusing 0x%lx and long cast in DBUG)
- Also fix printf-format warnings
Make the above mentioned warnings fatal.
- fix pthread_join on Windows to set return value.
Temporary table being created by outer statement
should not be visible to inner statement. And if
inner statement creates a table with same name.
The whole statement should fail with
ER_TABLE_EXISTS_ERROR.
Implemented by temporarily de-linking the TABLE_SHARE
being created by outer statement so that it remains
hidden to the inner statement.
mysqld maintains a list of TABLE objects for all temporary
tables created within a session in THD. Here each table is
represented by a TABLE object.
A query referencing a particular temporary table for more
than once, however, failed with ER_CANT_REOPEN_TABLE error
because a TABLE_SHARE was allocate together with the TABLE,
so temporary tables always had only one TABLE per TABLE_SHARE.
This patch lift this restriction by separating TABLE and
TABLE_SHARE objects and storing TABLE_SHAREs for temporary
tables in a list in THD, and TABLEs in a list within their
respective TABLE_SHAREs.
