Re: Why is this system swapping?

Sorry, I didn't attach vmstat, the system does actively swap pages. Not
to the point where it crawls, but for some brief periods the console
becomes a bit unresponsive. I am taking this as a sign to prevent future
problems.

anjan

-----Original Message-----
From: Jeff [mailto:threshar(at)torgo(dot)978(dot)org]
Sent: Wednesday, April 27, 2005 2:30 PM
To: Anjan Dave
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] Why is this system swapping?

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(at)jefftrout(dot)com>
http://www.jefftrout.com/
http://www.stuarthamm.net/