Hi I really don't like the idea to set innodb_flush_log_at_trx_commit to 2, the information in these tables is important. On the other hand there is nothing I can do from the point of view of the number of transactions. Each process run its own set of INSERTs and UPDATEs statements, so I can not reduce the number of transactions being executed.
Looking to the MySQL documentation: >> Since the rotation speed of a disk is typically at most 167 revolutions/second, that constrains the number of commits to the same 167th/second >> if the disk does not fool the operating system And that we are doing a LOT MORE INSERTs by second, I'm afraid maybe the only solution is go back to MyISAM :-( By the way this figure of 167 revolutions/second is based on what kind of hard disk? thanks Javier -----Original Message----- From: Marc Slemko [mailto:[EMAIL PROTECTED] Sent: 05 July 2004 17:58 To: Javier Diaz Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: Re: Concurrency Question On Mon, 5 Jul 2004 16:07:58 +0100 , Javier Diaz <[EMAIL PROTECTED]> wrote: > > We have changed all our tables to InnoDB and now the server is not able to > handle the load, even when we are not running the SELECTs statements against > these tables yet. > > As I mentioned in my email we make a lots of INSERTS and UPDATES in these > tables (more than 3000 per second). So far using MyISAM everything was OK, > but now when we moved the tables to InnoDB (to be able to make Read/Write > operations in these tables) the performance was down completely and the > server can not handle it. > > Does anyone have a rough idea when you change from MyISAM to InnoDB how the > performance is affected? That all depends on how you are using transactions. If you are trying to do each of these operations in a separate transaction, then definitely that will be a problem since transactions inherently have a certain cost to them since they need to commit changes to durable storage. If this is the case, then a horribly ugly "now you don't have durability any more in your transactions" hack you could try is setting innodb_flush_log_at_trx_commit to 2, see the docs for details. Be warned that doing so means you can loose committed transactions if the machine crashes. ________________________________________________________________________ This e-mail has been scanned for all viruses by Star Internet. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk ________________________________________________________________________ ________________________________________________________________________ This e-mail has been scanned for all viruses by Star Internet. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk ________________________________________________________________________ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
