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From:Dan Nelson Date:June 10 2009 6:38pm
Subject:Re: Available parallelism in MySQL community edition 5.1.34?
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In the last episode (Jun 10), Mike Spreitzer said:
> If I have a computer with many cores and multiple disks, disjoint
> filesystems on those disks, and enough I/O bandwidth in the machine to
> keep the disks busy, can MySQL keep those disks busy if I have it working
> on different databases at the same time?  If so, can one MySQL server
> process do that, or do I need multiple server processes?  If one process
> is enough, presumably I have to say something clever in my.cnf to make it
> happen; what would that be?  If it can be done with multiple server
> processes, can I get that from one MySQL installation (and if so, how) or
> do I need to somehow fool my package management system (RPM on RHEL) into
> doing multiple installations?

MySQL is a threaded server, so as long as your queries are accessing
different tables, each should be able to use one CPU each.  Multiple queries
on the same MyISAM table will queue up if there is a writer amongst them. 
If you are using a table engine that supports parallel access (innodb for
example) then multiple queries can write to the same table without blocking
readers.  Also, note that MySQL doesn't do query parallelism, so one query
will never use more than one CPU.

	Dan Nelson
Available parallelism in MySQL community edition 5.1.34?Mike Spreitzer10 Jun
  • Re: Available parallelism in MySQL community edition 5.1.34?Thomas A. McGonagle10 Jun
  • Re: Available parallelism in MySQL community edition 5.1.34?Dan Nelson10 Jun