Michael Schulz - 2004-03-16

we are using zope 2.6.4rc2, python 2.2.3, Python-MySQL 0.9.3b2, mysqlUserfolder 0.9.2, MySQL 4.0.16 after upgrading from Zope 2.5, MUF 0.5.1 and MySQL 3.23.32.
We use up to 60 MySQL Connection Objects out of 4 Zope-Instances before upgrading without any problems.

After the upgrade we are having problems with the amount of mysql threads/connections mysqluserfolder uses. While connections that are established via the zmysqlda get reused, mysqluserfolder threads seem to be used once and then sleep until the wait_timeout limit is reached. This leeds to the problem that at some point with high traffic no more mysql connections can be established at all and zope raises errors like "the zsql method xy is not connected to a database" or "cannot connect to mysql socket ..."  This point is reached far below the max_connections settings. The mysqld takes than about 99.9% CPU and cannot be stopped by /etc/init.d/mysql stop

Some settings aout of our MySQL config:
wait_timeout 3600
max_connections 3000

Has anyone experience with similar problems or can comment on mysql tuning parameters?

Cheers, Michael