/tmp doesn't seem to be much of a problem. I have about 1k worth of data in there and 72k in /var/tmp.

Would turning swap off help in tuning the database in this regard? top is reporting that there's 1.25GB of RAM free on a 2GB system so, in my estimation, there's no need for PostgreSQL to be swapped unless that free memory is Solaris caching files in RAM.


----- Original Message ----- From: "Greg Spiegelberg" <[EMAIL PROTECTED]>
Cc: "Kevin Schroeder" <[EMAIL PROTECTED]>; <pgsql-performance@postgresql.org>
Sent: Wednesday, January 19, 2005 9:07 AM
Subject: Re: [PERFORM] Swapping on Solaris

Alan Stange wrote:

Note that files in /tmp are usually in a tmpfs file system. These files may be the usage of swap that you're seeing (as they will be paged out on an active system with some memory pressure)

You can do a couple things with /tmp. Create a separate file system for it so it will have zero impact on swap and use the "noatime" mount option. Alternatively, limit the size of /tmp using the mount option "size=MBm" replacing "MB" with the size you want it to be in MBytes. If your application uses /tmp heavily, be sure to put it on a speedy, local LUN.

Finally, just as everyone suggests upgrading to newer postgresql releases, you probably want to get to a newer Solaris release.

If you really want to avoid swapping I'd suggest tuning your database first with swap turned off and put it under a "normal" load while watching both top and vmstat. When you're happy with it, turn swap back on for those "heavy" load times and move on.


Greg Spiegelberg
 Product Development Manager
 Cranel, Incorporated.
 Phone: 614.318.4314
 Fax:   614.431.8388
Technology. Integrity. Focus.

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