# of mysql idle processes

[csn]

Is there a way to reduce the number of mysql processes? I think they're just idling waiting for connections.

USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
mysql 26641 0.0 4.5 111296 23032 ? S Feb04 19:55 /usr/sbin/mysqld-
mysql 26643 0.0 4.5 111296 23032 ? S Feb04 0:03 /usr/sbin/mysqld-
mysql 26644 0.0 4.5 111296 23032 ? S Feb04 0:00 /usr/sbin/mysqld-
mysql 26645 0.0 4.5 111296 23032 ? S Feb04 1:27 /usr/sbin/mysqld-
mysql 26646 0.0 4.5 111296 23032 ? S Feb04 4:49 /usr/sbin/mysqld-
mysql 26647 0.0 4.5 111296 23032 ? S Feb04 5:44 /usr/sbin/mysqld-
mysql 26648 0.0 4.5 111296 23032 ? S Feb04 0:00 /usr/sbin/mysqld-
mysql 26649 0.0 4.5 111296 23032 ? S Feb04 0:04 /usr/sbin/mysqld-
mysql 26650 0.0 4.5 111296 23032 ? S Feb04 6:22 /usr/sbin/mysqld-
mysql 26651 0.0 4.5 111296 23032 ? S Feb04 21:53 /usr/sbin/mysqld-
mysql 26652 0.0 4.5 111296 23032 ? S Feb04 0:00 /usr/sbin/mysqld-
mysql 27454 0.4 4.5 111296 23032 ? S Mar21 6:15 /usr/sbin/mysqld-
mysql 27512 0.4 4.5 111296 23032 ? S Mar21 6:35 /usr/sbin/mysqld-
mysql 27514 0.3 4.5 111296 23032 ? S Mar21 5:55 /usr/sbin/mysqld-
mysql 27518 0.3 4.5 111296 23032 ? S Mar21 5:51 /usr/sbin/mysqld-
mysql 27522 0.4 4.5 111296 23032 ? S Mar21 6:12 /usr/sbin/mysqld-
mysql 27526 0.4 4.5 111296 23032 ? S Mar21 6:37 /usr/sbin/mysqld-
mysql 2455 0.2 4.5 111296 23032 ? S 00:27 2:19 /usr/sbin/mysqld-
mysql 2457 0.2 4.5 111296 23032 ? S 00:27 2:00 /usr/sbin/mysqld-

[ultraslacker]

That's normal - creating connections is relatively expensive, so a connection pool is used via pconnects in php/mysql. You can set max mysql persistent connections in mysql section of php.ini, the default is 25.

Depending on the makeup of your server, you may be better off not using pconnects. But these are idle processes and as long as they are not in the 100's shouldn't impede performance.

[csn]

I'm not using persistant connections though (they're off in php.ini). I don't think there's a SET var for min processes, I'll have to see if there's something in the configure options for compiling.

[ultraslacker]

If you are not using pconnects, then these processes are being created as needed - set interactive_timeout to kill idles.

[csn]

Nah, interactive_timeout doesn't change it. I stopped everything that would be connecting to mysql (primarily the web server), then stopped/started mysql - it starts 12 mysql processes right off. I've tried changing just about every var that looks like it might affect this, but no changes. Blah, I dunno - think it might be related to innodb - didn't do this before I started using them. There are some innodb file io thread vars.