Re: a heavy duty operation on an "unused" table kills my server

From: Pierre Frédéric Caillaud <lists(at)peufeu(dot)com>
To: "Eduardo Piombino" <drakorg(at)gmail(dot)com>, "Craig James" <craig_james(at)emolecules(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: a heavy duty operation on an "unused" table kills my server
Date: 2010-01-14 16:16:11
Message-ID: op.u6i549rvcke6l8@soyouz
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> "high CPU usage" It might very well be "high IO usage".

Try this :

Copy (using explorer, the shell, whatever) a huge file.
This will create load similar to ALTER TABLE.
Measure throughput, how much is it ?

If your server blows up just like it did on ALTER TABLE, you got a IO
system problem.
If everything is smooth, you can look into other things.

How's your fragmentation ? Did the disk ever get full ? What does the
task manager say (swap in/out, disk queue lengthn etc)

PS : try a separate tablespace on another disk.

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