…, preventing rows from becoming orphaned. But then we learn that the enforcement of foreign keys incurs a significant performance overhead.1,2 MySQL allows us to set FOREIGN_KEY_CHECKS=0 to disable enforcement of RI when the overhead is too high. But if you later restore enforcement, MySQL does not immediately scan all…
Post: Percona Server 5.1.59-13.0
October 16, 2011 By Leave a Comment
…commit. That makes prefetch simple but has high overhead from locking rows only to undo changes at…the threshold specified, it will be killed. This prevents users from blocking purge by mistake. Block … KEY. #851674 (Alexey Kopytov). Backported fix for MySQL bug #53761 (Wrong estimate for RANGE query …
Post: Percona Server 5.5.16-22.0
October 16, 2011 By 2 Comments
…and from the Percona Software Repositories). Based on MySQL 5.5.16, including all the bug …commit. That makes prefetch simple but has high overhead from locking rows only to undo changes at …the threshold specified, it will be killed. This prevents users from blocking purge by mistake. Block startup…
Post: The Doom of Multiple Storage Engines
May 8, 2010 By 22 Comments
… engine transactions which require a lot of complications and performance overhead. MySQL has to do several fsync() calls per transaction commit to… cases. We also get into synchronization aspects making backup which prevents from having hot backup in many cases. Replication Support for…
Post: MySQL MyISAM Active Active Clustering - looking for trouble ?
March 15, 2007 By 4 Comments
… This configuration adds effectively global table locks besides extra overhead you get from external locking. Plus key … for large tables. Furthermore as I remember MySQL simply was not repairing corrupted tables in … works as it does not allow to prevent race condition. Of course sometimes your Boss …
Post: Preprocessing Data
August 8, 2011 By 3 Comments
… TRIGGERs) does additional calculations or data insertions. This adds some overhead when data is being inserted, but according to your business… form of batch processing. Examples could be reporting, updating caches (preventing cache stampedes) and counter tables. Prefetching If there is a…
