…, thread declared inside InnoDB 334 mysql tables in use 4, locked 4 3264 lock struct(s), heap size 440760, 799203 row lock(s) MySQL thread id 38, OS thread handle 0x2b3c1c776940, query id 16838101 localhost root Copying to tmp table create table t as SELECT…
Post: SELECT LOCK IN SHARE MODE and FOR UPDATE
August 6, 2006 By 51 Comments
…mysql> commit; Query OK, 0 rows affected (0.01 sec) SESSION2: mysql> select * from tst; Empty set (0.00 sec) mysql> select * from tst lock…missing in Innodb locking.? In my oppinion few rather important peices missing in Locking implementation of Innodb are: Lock table Innodb can lock tables but it …
Post: INSERT INTO ... SELECT Performance with Innodb tables.
July 12, 2006 By 22 Comments
… Innodb tables perform non locking reads, meaning unless you use some modifiers such as LOCK IN SHARE MODE or FOR UPDATE, SELECT statements will not lock…fetching rows, thread declared inside InnoDB 3 mysql tables in use 1, locked 1 2539 lock struct(s), heap size 224576 MySQL thread id 1794751, query…
Post: Innodb Table Locks
July 31, 2012 By 4 Comments
…locking table for write (on MySQL Level) before operation and unlocking it straight after. Not so for Innodb. Unless table is being locked explicitly Innodb “converts” table lock…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…MySQL manual, especially the option and variable reference table…Innodb_row_lock_current_waitsblogpercona.commanual Innodb_row_lock_timeblogpercona.commanual Innodb_row_lock_time_avgblogpercona.commanual Innodb_row_lock_time_maxblogpercona.commanual Innodb_row_lock_waitsblogpercona.commanual Innodb…
Post: Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit
November 24, 2011 By 2 Comments
…MySQL server. Let’s take a recent 5.1 bzr version (pre-5.1.61) and a single test, innodb_plugin.innodb…table_state) (sql_show.cc:6238) ==9090== by 0x6A5E0C: JOIN::exec() (sql_select.cc:1863) ==9090== by 0x6A7D72: mysql_select(THD*, Item***, TABLE…
Post: InnoDB's gap locks
March 27, 2012 By 15 Comments
… a SELECT. They only occur if you do UPDATE or DELETE or SELECT FOR UPDATE. InnoDB provides REPEATABLE READ for read-only SELECT, but… MySQL thread id 3, OS thread handle 0x7f84a78ba700, query id 163 localhost msandbox TABLE LOCK table `test`.`t` trx id 72C lock mode IX RECORD LOCKS…
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
…tables: 0 Tmp_disk_tables: 0 Tmp_table_sizes: 0 # InnoDB_trx_id: 12F14 SET timestamp=1347398285; select…mysql> explain select * from sbtest a,sbtest b where a.id=5 and b.id=a.k; +—-+————-+——-+——-+—————+———+———+——-+——+——-+ | id | select_type | table…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
…use FLUSH TABLES WITH READ LOCK to temporary make MySQL …SELECT statement to complete in order to complete locking tables. This means if you have workload which includes some very long SELECT…Innodb tables and you’re not actively changing users, stored procedures etc (which are stored in MyISAM tables…
Post: Avoiding auto-increment holes on InnoDB with INSERT IGNORE
November 29, 2011 By 8 Comments
… to MySQL 5.1.22 InnoDB used a method to access that counter values called “Traditional”. This one uses a special table lock called… later the lock algorithm for the auto_increment value is configurable and you can select from different algorithms using the innodb_autoinc_lock_mode…
