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Date: Wed, 23 Jan 2013 11:53:57 -0500
From: AJ Weber <aweber@comcast.net>
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To: pgsql-performance@postgresql.org
Subject: autovacuum fringe case?
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I have a server that is IO-bound right now (it's 4 cores, and top 
indicates the use rarely hits 25%, but the Wait spikes above 25-40% 
regularly).  The server is running postgresql 9.0 and tomcat 6.  As I 
have mentioned in a previous thread, I can't alter the hardware to add 
disks unfortunately, so I'm going to try and move postgresql off this 
application server to its own host, but this is a production 
environment, so in the meantime...

Is it possible that some spikes in IO could be attributable to the 
autovacuum process?  Is there a way to check this theory?

Would it be advisable (or even permissible to try/test) to disable 
autovacuum, and schedule a manual vacuumdb in the middle of the night, 
when this server is mostly-idle?

Thanks for any tips.  I'm in a bit of a jam with my limited hardware.

-AJ


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