Re: Moving to a faster machine does not improve performance

[Stephane Deverly]

Yes we did. We tried to put all what we can in memory.
But, just after we switched from the old to the new server, with the same my.cnf and the same application, we didn't see any improvement. The load was even higher.

If it can help, the database is used for queuing system. We have 300 daemons running on different machines which try to pick up things to do from the database. This is done by trying to change a status from 'ready' to 'assigned'. Something like :
UPDATE table SET status='assigned' WHERE status='ready'

We are using InnoDb tables because of the row locking mechanism. Can it be that we have too many "collisions", I mean too many daemons trying to access the same rows at the same time, and that whatever server me may have, we are bound by that ?

We are not using transactions, in an attempt to not overload the server. But, that means that we have to do some kind of rollbacks ourself : sometimes we need to put back things as they were. I guess that we are introducing some disk access where we could only have memory / cpu usage. Should transactions be used in a ssytem meant to be as fast as possible ?