Devanada, normally you do not need to tune this option at all.
I introduced the option when certain Linux binaries showed 'thread thrashing' at high concurrency. Setting the option to 1 or 2 could in some cases alleviate the problem. You can experiment by setting the option to 500 to disable restrictions on concurrent operations. I am considering changing the default value to 500, because we have not seen 'thread thrashing' on any platform for a long while. Best regards, Heikki Innobase Oy InnoDB - transactions, row level locking, and foreign keys for MySQL InnoDB Hot Backup - a hot backup tool for InnoDB which also backs up MyISAM tables http://www.innodb.com/order.php Order MySQL support from http://www.mysql.com/support/index.html ........................... Hi, This is a question about optimization of mysql's InnoDB performance ... quoting the doc's > "The default value is 8. If you have low performance and |SHOW INNODB STATUS| reveals many threads waiting for semaphores, > you may have thread thrashing and should try setting this parameter lower or higher..... The default value is 8. If you have low > performance and |SHOW INNODB STATUS| reveals many threads waiting for semaphores, you may have thread thrashing and > should try setting this parameter lower or higher." What is a reasonable value for a dual Xeon 2.8Ghz with 6 disks? we are currently running with innodb_thread_concurrency=16. Each DB has 200-400 active php clients, and there appears to be quite a large backup within innodb, based on this. Any suggestions? Or experience with setting this option to 500? Thanks :) Devananda Neopets, Inc -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]