Re: Why is this system swapping? - Mailing list pgsql-performance

From Jeff
Subject Re: Why is this system swapping?
Date
Msg-id 7a617f4f4c47b0235c56d4a0ec624e51@torgo.978.org
Whole thread Raw
In response to Why is this system swapping?  ("Anjan Dave" <adave@vantage.com>)
List pgsql-performance
On Apr 27, 2005, at 1:48 PM, Anjan Dave wrote:

> As you can see the system starts utilizing swap at some point, with so
> many processes. Some time ago we had decided to keep the connections
> from the pool open for longer

You've shown the system has used swap but not that it is swapping.
Having swap in use is fine - there is likely plenty of code and whatnot
that is not being used so it dumped it out to swap. However if you are
actively moving data to/from swap that is bad. Very bad. Especially on
linux.

To tell if you are swapping you need to watch the output of say, vmstat
1 and look at the si and so columns.

Linux is very swap happy and likes to swap things for fun and profit.

--
Jeff Trout <jeff@jefftrout.com>
http://www.jefftrout.com/
http://www.stuarthamm.net/


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