| Bug #55642 | Please document innodb_thread_concurrency=0 impact on SHOW ENGINE INNODB STATUS | ||
|---|---|---|---|
| Submitted: | 30 Jul 2010 2:33 | Modified: | 19 Jul 2012 23:28 |
| Reporter: | Roel Van de Paar | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: Documentation | Severity: | S3 (Non-critical) |
| Version: | OS: | Any | |
| Assigned to: | John Russell | CPU Architecture: | Any |
[30 Jul 2010 3:13]
Roel Van de Paar
Verifying. I can reproduce '1 queries inside InnoDB' <vs> '0 queries inside InnoDB'. 'queries in queue' not tested.
[5 Aug 2010 11:09]
Marko Mäkelä
The function srv_conc_force_enter_innodb() and related functions skip all bookkeeping when innodb_thread_concurrency=0. SHOW ENGINE INNODB STATUS is displaying the default value of the counter.
[19 Jul 2012 23:28]
John Russell
Added the extra info under the description of the innodb_thread_concurrency config option. Applied the fix to the 5.1, 5.5, and 5.6 Ref Mans.
Description: Please update the documentation to explain that setting the value of innodb_thread_concurrency = 0 disables the "queries inside InnoDB" and "queries in queue" counters in SHOW ENGINE INNODB STATUS ("ROW OPERATIONS" section) and that if users (or monitoring software like MEM and/or others) need these numbers then they should set the value of this option to a high/tuned number. How to repeat: mysql1> set @@global.innodb_thread_concurrency=2; mysql1> alter table sometable engine=innodb; mysql2> show engine innodb status\G 1 queries inside InnoDB, 0 queries in queue mysql1> set @@global.innodb_thread_concurrency=0; mysql1> alter table sometable engine=innodb; mysql2> show engine innodb status\G 0 queries inside InnoDB, 0 queries in queue Suggested fix: After documenting this in the MySQL manual, it may be good to mention this in the MEM manual also (re-assign bug to MEM team after updating main manual).