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.
----------------------------------------------------------
revno: 2630.4.35
committer: Konstantin Osipov <konstantin@mysql.com>
branch nick: mysql-6.0-3726
timestamp: Wed 2008-06-25 16:44:00 +0400
message:
Fix a MyISAM-specific bug in the new implementation of
LOCK TABLES (WL#3726).
If more than one instance of a MyISAM table are open in the
same connection, all of them must share the same status_param.
Otherwise, unlock of a table may lead to lost records.
See also comments in thr_lock.c.
The problem was that new lock types were being added without a
corresponding description. Since the lock types (enum values)
are used as indices to the description array, the descriptions
could be shifted depending on the lock type. The solution is to
ensure that every lock type has a correspondent description.
upgrading lock, even with low_priority_updates
The problem is that there is no mechanism to control whether a
delayed insert takes a high or low priority lock on a table.
The solution is to modify the delayed insert thread ("handler")
to take into account the global value of low_priority_updates
when taking table locks. The value of low_priority_updates is
retrieved when the insert delayed thread is created and will
remain the same for the duration of the thread.
The problem is that when statement-based replication was enabled,
statements such as INSERT INTO .. SELECT FROM .. and CREATE TABLE
.. SELECT FROM need to grab a read lock on the source table that
does not permit concurrent inserts, which would in turn be denied
if the source table is a log table because log tables can't be
locked exclusively.
The solution is to not take such a lock when the source table is
a log table as it is unsafe to replicate log tables under statement
based replication. Furthermore, the read lock that does not permits
concurrent inserts is now only taken if statement-based replication
is enabled and if the source table is not a log table.
value" error even though the value was correct): a C function in my_getopt.c
was taking bool* in parameter and was called from C++ sql_plugin.cc,
but on some Mac OS X sizeof(bool) is 1 in C and 4 in C++, giving funny
mismatches. Fixed, all other occurences of bool in C are removed, future
ones are blocked by a "C-bool-catcher" in my_global.h (use my_bool).
The value of "low-priority-updates" option and the LOW PRIORITY
prefix was taken into account at parse time.
This caused triggers (among others) to ignore this flag (if
supplied for the DML statement).
Moved reading of the LOW_PRIORITY flag at run time.
Fixed an incosistency when handling
SET GLOBAL LOW_PRIORITY_UPDATES : now it is in effect for
delayed INSERTs.
Tested by checking the effect of LOW_PRIORITY flag via a
trigger.
Fixed compile-pentium64 scripts
Fixed wrong estimate of update_with_key_prefix in sql-bench
Merge bk-internal.mysql.com:/home/bk/mysql-5.1 into mysql.com:/home/my/mysql-5.1
Fixed unsafe define of uint4korr()
Fixed that --extern works with mysql-test-run.pl
Small trivial cleanups
This also fixes a bug in counting number of rows that are updated when we have many simultanous queries
Move all connection handling and command exectuion main loop from sql_parse.cc to sql_connection.cc
Split handle_one_connection() into reusable sub functions.
Split create_new_thread() into reusable sub functions.
Added thread_scheduler; Preliminary interface code for future thread_handling code.
Use 'my_thread_id' for internal thread id's
Make thr_alarm_kill() to depend on thread_id instead of thread
Make thr_abort_locks_for_thread() depend on thread_id instead of thread
In store_globals(), set my_thread_var->id to be thd->thread_id.
Use my_thread_var->id as basis for my_thread_name()
The above changes makes the connection we have between THD and threads more soft.
Added a lot of DBUG_PRINT() and DBUG_ASSERT() functions
Fixed compiler warnings
Fixed core dumps when running with --debug
Removed setting of signal masks (was never used)
Made event code call pthread_exit() (portability fix)
Fixed that event code doesn't call DBUG_xxx functions before my_thread_init() is called.
Made handling of thread_id and thd->variables.pseudo_thread_id uniform.
Removed one common 'not freed memory' warning from mysqltest
Fixed a couple of usage of not initialized warnings (unlikely cases)
Suppress compiler warnings from bdb and (for the moment) warnings from ndb
This problem could happen when show table status get outdated copy
of TABLE object from table cache.
MyISAM updates state info when external_lock() method is called. Though
I_S does not lock a table to avoid deadlocks. If I_S opens a table which
is in a table cache it will likely get outdated state info copy.
In this case shared state copy is more recent than local copy. This problem
is fixed by correctly restoring myisam state info pointer back to original
value, that is to shared state.
Affects MyISAM only. No good deterministic test case for this fix.
Optimised version of ADD/DROP/REORGANIZE partitions for
non-NDB storage engines.
New syntax to handle REBUILD/OPTIMIZE/ANALYZE/CHECK/REPAIR partitions
Quite a few bug fixes
Fixed portability problem with bool in C programs
Moved close_thread_tables out from LOCK_thread_count mutex (safety fix)
my_sleep() -> pthread_cond_timedwait()
The idea of the patch
is that every cursor gets its own lock id for table level locking.
Thus cursors are protected from updates performed within the same
connection. Additionally a list of transient (must be closed at
commit) cursors is maintained and all transient cursors are closed
when necessary. Lastly, this patch adds support for deadlock
timeouts to TLL locking when using cursors.
+ post-review fixes.
myisam_max_extra_sort_file_size is depricated
Ensure that myisam_data_pointer_size is honoured when creating new MyISAM files
Changed default value of myisam_data_pointer_size from 4 to 6 to get rid of 'table-is-full' errors
updated manual about table lock counter
fixed coredump in DROP DATABASE with long bogus name by non-root user
fixed bug in handling STOP immediately after ROTATE
added test case for buffer overrun on DROP DATABASE by non-root user
added test case for the STOP bug in replication
