…was completed regardless of its state before updating. This caused some problems for some users,…New Features: Percona Server for MySQL has implemented priority connection scheduling for the Thread Pool. (Alexey …malloc call in the read_view_create_low() in most cases. This significantly improves …
Post: Percona Server for MySQL 5.5.30-30.2 now available
April 10, 2013 By 10 Comments
… New Features: Percona Server for MySQL has implemented priority connection scheduling for the Thread Pool. (Alexey Kopytov… malloc call in the read_view_create_low() in most cases. This significantly improves InnoDB … can be reported on the launchpad bug tracker. UPDATE[18-04-2013]: There was a RPM …
Post: Using MyISAM in production
June 17, 2006 By 36 Comments
… MySQL treats updates as higher priority operations. You can use SELECT HIGH_PRIORITY or UPDATE LOW_PRIORITY to adjust that or you can simply set low_priority_updates option. Anyway default behavior means any UPDATE statement which…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…log_warningsblogpercona.commanual long_query_timeblogpercona.commanual low_priority_updatesblogpercona.commanual lower_case_file_systemblogpercona…. tx_isolationblogpercona.commanual unique_checksblogpercona.commanual updatable_views_with_limitblogpercona.commanual Uptimeblogpercona.commanual …
Post: SELECT LOCK IN SHARE MODE and FOR UPDATE
August 6, 2006 By 51 Comments
… – lock will not need to be upgraded when update happens. SELECT FOR UPDATE also blocks access to the data using LOCK IN… deadlock victum scheduling At this point transaction which made least updates is killed to resolve deadlock. Which means if transaction takes…; – A lot of shared locks on Innodb table but no updates. Supporting MySQL hints “HIGH_PRIORITY” and “LOW_PRIORITY” would probably be good start.
Post: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
…” (deleted rows) which can help significantly. delay_key_write Delay updating indexes for MyISAM tables. Good for performance but tables will… also could use this feature. low_priority_updates If enabled selects will get higher priority than updates and waiting update will not stall all new selects…
Comment: Why MySQL could be slow with large tables ?
June 20, 2007 By 141 Comments
… the following activity: Per day: 1. INSERTS: 1,000 2. UPDATES: 200 3. SELECTS: 1 million Since this is a predominantly…/log/mysql-slow.log sql-mode=TRADITIONAL concurrent_insert=2 low_priority_updates=1 The problem was that at about 3pm GMT the… record as mentioned above (a small fraction of INSERTs and UPDATEs)? We explored a bunch of issues including questioning our hardware…
Comment: Percona build7 with latest patches
November 20, 2008 By 26 Comments
… MySQL 32bit) [mysqld] max_connections=2000 key_buffer_size=200M low_priority_updates=1 table_cache = 8000 sort_buffer_size = 2097152 innodb_file…
Post: Knowing what pt-online-schema-change will do
November 1, 2012 By 1 Comment
….`guest_country` CREATE TRIGGER `pt_osc_test_t_upd` AFTER UPDATE ON `test`.`t` FOR EACH ROW REPLACE INTO `test`.`_t…`) Not copying rows because this is a dry run. INSERT LOW_PRIORITY IGNORE INTO `test`.`_t_new` (`id`, `guest_language`, `guest_country…: Not copying rows because this is a dry run. INSERT LOW_PRIORITY IGNORE INTO `test`.`_t_new` (`id`, `guest_language`, `guest_country…
Comment: Managing Slave Lag with MySQL Replication
March 26, 2008 By 15 Comments
Setting LOW_PRIORITY on UPDATE/DELETE/INSERT queries may also cause a replication lag. It works fine on the master, but when it is being replicated to the slaves, it will cause the replication thread to wait until there are no more readers on that table.
