From: Keith Murphy
Date: December 15 2009 3:46pm
Subject: the mystery of the missing mysql.sock file
List-Archive: http://lists.mysql.com/mysql/219775
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Take one perfectly functional production server running 5.0.77. It has been
up and running under load for quite some time. I am using xtrabackup for
backups and suddenly three or four days ago backup stop running.

Investigation shows that the socket file '/tmp/mysql.sock' is no longer
there. The mysql server itself is still functioning .. you can specify
--host=localhost instead of --socket=/tmp/mysql.sock so the mysql client
uses tcp/ip instead of the socket file to connect to the server.


   - Permissions did not change on the /tmp directory..I checked.
   - There are no errors in the .err log.
   - No cron jobs clearing out /tmp.
   - SHOW VARIABLES LIKE '%sock%' displays the proper socket location



Any thoughts? I have seen this type of thing occasionally before, but never
taken the time to really investigate. I would just restart the server. I
will end up having to do so in this case, but I would really like to find
out WHY this happened. Is this is bug in the server code? I can't come up
with any other explanation. I would love for this to be explainable!

thanks,

keith

-- 
Chief Training Officer
Paragon Consulting Services
850-637-3877

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