… internal XA implementation. This did two things: it disabled group commit, and it added an extra fsync per commit. The extra fsync is… use XA transactions, you can disable this variable to reduce the number of disk flushes and get better InnoDB performance. Having innodb_support_xa enabled…
Post: Group commit and XA
May 19, 2006 By 8 Comments
Returning to post Group commit and real fsync I made several experiments: I ran sysbench update_key benchmarks … and —innodb-support-xa=0 (default value is 1). Results (in transactions / sec) threads without —log-bin —log-bin —log-bin and —innodb_support-xa=0…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…innodb_status_fileblogpercona.commanual innodb_strict_modeblogpercona.commanual innodb_support_xablogpercona.commanual innodb_sync_spin_loopsblogpercona.commanual innodb_table_locksblogpercona.commanual innodb_thread_concurrencyblogpercona.commanual innodb…
Comment: Tuning for heavy writing workloads
October 15, 2009 By 9 Comments
… it). Whether innodb_support_xa is needed or not is depend on the each user. If innodb_support_xa=1 and using binlog, 2 times fsync() is done for the each transaction. It is “prepare” fsync() and “commit” fsync(), the…
Comment: Benchmarking Galera replication overhead
October 14, 2011 By 12 Comments
… which settings did you use for sync_binlog, innodb_support_xa? 3) What values of innodb_flush_log_at_trx_commit did you use… may coming from writing write sets to disk.” Does Galera fsync the write set to disk after every single transaction? Or…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
… get 2000 fsync/sec or more which is typically enough. Q23: Rumor has it that if you disable the new XA support (which… write and the InnoDB log flush with a mutex in 5.1, to implement XA, and switching off the XA will not remove that serialization. MySQL’s binlog and InnoDB‘s log must have…
Post: MySQL 4 to MySQL 5 Upgrade performance regressions
June 6, 2007 By 8 Comments
….0 of MySQL being slow but few queries being “inside innodb” and potentially even empty queue. This is because bottleneck happens… statement transactions. Looking at SHOW INNODB STATUS you would notice large amount of log writes and fsyncs per second which matches your… of 3 things to get some of your performance back. XA support has its overhead anyway so you may not get same…
Comment: Jeremy Cole on MySQL Replication
June 17, 2006 By 12 Comments
…. 2) Right in MySQL binary log file has to be XA source as well… otherwise it can run out of sync… 5.0 you can disable innodb_xa_support and you can get binary log possibly out of sync with innodb transactional log. However it….mysqlperformanceblog.com/2006/05/19/group-commit-and-xa/ – disabling XA saves you from extra fsync which allows to double results but results…
Post: When would you use SAN with MySQL ?
March 9, 2009 By 18 Comments
… latency critical. Now what is about MySQL/Innodb specifics ? First, in MySQL if you’re …do more than one fsync() for the log because it internally implements XA to synchronize with binary … replication between directly attached volumes. Now with support for Dolphin Interconnect it can also offer …
