Hello Gary,
Gary Smith wrote:
Mike,
It's not a connection pooling issue per say. We have several boxes running
spam assassin, sqlgrey and postfix (via mysql). Normally these components work
great. SA and sqlgrey both have a fixed number of connections, around 16, that
they are generally actively using unless we get a burst of email, at which time
they will increase by a few. The problem is that Postfix has been receiving a
higher level than normal of emails as we have taken 50% of our servers offline
at this location (setting them up at a new location). We're also have this
bouncing across a couple different firewalls, so for some reason, the
conneciton to mysql is generating a larger number of these:
090407 12:26:42 [Warning] Aborted connection 972479 to db: 'db' user: 'user'
host: 'host' (Got an error reading communication packets)
We do know the network isn't optimal right now and are working to fix the
issues but we are hoping to get by just for the short term.
But that leads back to the original question about increase the connection
error cutoff before banning a host.
We are using 5.1.32 with INNODB tables.
________________________________________
From: mos [mo...@fastmail.fm]
Sent: Tuesday, April 07, 2009 9:18 AM
To: mysql@lists.mysql.com
Subject: Re: flush-host problem
At 10:39 AM 4/7/2009, Gary Smith wrote:
I have system that is generating a larger than normal number of connection
errors. We know why the errors are occuring and are working to resolve
them (connectivity and load issue on the client). The question is, how
can I tweak mysql to tolerate a higher level than normal of bad
connections before banning the host.
What happens is that when we have 300-500 connections a few random ones
will get mucked up during a heavier than normal load on the client. I
have set the max connections to 3000 (which we never get close to).
So, if there a config/startup setting to tweak to ease the banning of bad
connetions thus reducing the need for me to continually "mysqladmin
flush-host" on the server?
--
...
The server generates those "Aborted connection" messages under the
following circumstances:
1) The server was trying to pass information to the client and the
client stopped being there.
2) The client sat idle beyond the wait_timeout setting.
3) There was some kind of networking interference (such as a VPN or
proxy server closing an idle connection) or bad connections.
Look at your SHOW PROCESSLIST report. If it shows many connections that
have been idle for more than 30 seconds or so, then you need to change
your client software behavior. If these are pooled connections, make
sure your idle connection timeout for the pool (part of the pool
configuration) is set to a value smaller than wait_timeout. Otherwize
you need to audit your client code to ensure that it is calling the
appropriate close() function for the library it is using to connect to
the MySQL server. That will release the connection and allow the server
to reallocate those resources to handling the commands for the live (and
not idle) connections.
For additional reasons for these errors, please peruse:
http://dev.mysql.com/doc/refman/5.0/en/communication-errors.html
Warmest regards,
--
Shawn Green, MySQL Senior Support Engineer
Sun Microsystems, Inc.
Office: Blountville, TN
--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
