May 25, 2012

Post: Avoiding auto-increment holes on InnoDB with INSERT IGNORE

MySQL 5.1.22 InnoDB used a method to access that counter values called “Traditional”. This one uses a special table lock called AUTO-INC that remains until the end of the query or transaction. Because of this, two queries can’t have the AUTO-INC lock…/REPLACE uses a light-weight mutex instead of a table lock on AUTO-INC. We have recovered the concurrency and the performance but…

Post: InnoDB auto-inc scalability fixed

… of customers who was affected by InnoDB auto-inc. For several of them we even advised to replace auto-inc column by that or another… system variable innodb_autoinc_lock_mode which determines behavior of InnoDB for tables with autoinc. I do not want to copy-paste MySQL documentation…

Post: Identifying the load with the help of pt-query-digest and Percona Server

… enable logging atomically, not just for new connections as in MySQL. This is very helpful for measurement as otherwise we might….001414 # InnoDB_rec_lock_wait: 0.000000 InnoDB_queue_wait: 0.000000 # InnoDB_pages_distinct: 973 SET timestamp=1325146286; select count(*) from auto_inc; Note that…

Comment: InnoDB auto-inc scalability fixed

…, needed. Imagine, how better the world will be if only MySQL realized the importance of back porting this quickly. James, I… worth it. The *thing* is that auto-inc table locking issue makes InnoDB inefficient for OLTP environments where an AUTO-INC column is being used. Frank

Post: Drilling down to the source of the problem

INNODB STATUS showed as waiting on famous Innodb AUTO-INC lock. That would be an easy excuse to blame everything on this lock, suggest upgrading to MySQL… long letting hundreds of AUTO-INC insert to pile up. This was also very interesting case about optimal innodb_thread_concurrency. I continue…

Post: Hacking to make ALTER TABLE online for certain changes

… well with both – InnoDB and MyISAM. Now that more and more folks hit the InnoDB auto-inc scalability issue with MySQL 5.0 and older versions, employing other techniques to maintain the PK auto incremental becomes… sec) — 2. mysql> FLUSH TABLES WITH READ LOCK; Query OK, 0 rows affected (0.00 sec) — 3. mysql> ^Z [1]+ Stopped mysql test # mv…

Comment: InnoDB auto-inc scalability fixed

[...] MySQL InnoDB 的 auto-increment 會造成 INSERT 時使用 table-level lock 的 bug 終於修正 (從 2006 年一月就進 MySQL 回報系統的 bug),下個 5.1 的版本 (預定是 5.1.22) 就會包括在裡面:InnoDB auto-inc scalability fixed。 [...]