[vox-tech] php-cgi hanging on semop()

[Troy Arnold]

On Wed, Nov 24, 2010 at 04:59:53PM -0800, Bill Kendrick wrote:
> 
> So I'm noticing some stability issues with a website.
> 
> * lighttpd 1.4.x
> * php 5.3.x
> * mysql 5.1.x
> 
> The symptoms to the outside world include lagging connections and,
> eventually, Error 500s from the webserver.
> 
> Internally, I run "mytop" (basically, a 'top'-like interface that
> parses the results of a "show full processlist" query).  mytop shows
> me what connections are active.
> 
> Typically, most of our connections are relatively active (only idle a
> couple of seconds, at most; If the website's not very busy, the idle
> time in some of them can climb in idleness).
> 
> However, in the situation I'm seeing, all of the connections from the
> webserver are idle, and their idle times continue to increase.
> Basically, the current connections between the website and the
> database aren't doing anything (not running queries for the website),
> and are just sitting there exhausting MySQL's connection pool.

What is the output of:
mysql> show variables like '%timeout%';

> Since this has only started happening recently, and usually after-hours,
> my quick-fix has been to do this:

There have been some package updates to mysql-server in both Debian/Ubuntu
and RHEL lately.  Maybe your problem started there?  A couple of ideas:

Do you need to run mysql_upgrade against your database ?
Did your server's my.cnf get changed recently?

mysqlcheck your tables?


-t