What would be the best value range for effective_cache_size on Postgres 7.3.2, assuming say 1.5 GB of RAM and shared_buffers set to 8192, and shmmax set to 750mb?
And what are the most important factors one should take into account in determining the value? > -----Original Message----- > From: scott.marlowe [SMTP:[EMAIL PROTECTED] > Sent: 01 July 2003 02:56 > To: Michael Mattox > Cc: Hilary Forbes; [EMAIL PROTECTED] > Subject: Re: [PERFORM] Version 7 question > > 8192 is only 64 megs of RAM, not much, but a good number. Keep in mind > that the kernel tends to be better at buffering huge amounts of disk, > while postgresql is better left to use buffers that are large enough for > the current working set (i.e. not your whole database, just the largest > amount of data you're slinging about on a regular basis in one query.) > > On a machine with 1.5 gig of RAM, I've found settings as high as 32768 > (256 megs of ram) to run well, but anything over that doesn't help. Of > course, we don't toss around more than a hundred meg or so at a time. If > > our result sets were in the gigabyte range, I'd A: want more memory and B: > > Give more of it to postgresql. > > The original poster was, I believe running 7.0.x, which is way old, so no, > > I don't think there was an equivalent of effective_cache_size in that > version. Upgrading would be far easier than performance tuning 7.0. since > > the query planner was much simpler (i.e. more prone to make bad decisions) > > in 7.0. > > On Tue, 1 Jul 2003, Michael Mattox wrote: > > > I have my shared buffers at 8192 and my effective cache at 64000 (which > is > > 500 megs). Depends a lot on how much RAM you have. I have 1.5 gigs and > > I've been asking my boss for another 512megs for over a month now. I > have > > no idea if my buffers are too high/low. > > > > Michael > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > > [mailto:[EMAIL PROTECTED] Behalf Of Hilary > > > Forbes > > > Sent: Tuesday, July 01, 2003 2:10 PM > > > To: [EMAIL PROTECTED] > > > Subject: [PERFORM] Version 7 question > > > > > > > > > I'm just trying to improve performance on version 7 before doing > > > some tests and hopefully upgrading to 7.3. > > > > > > At the moment we have > > > B=64 (no of shared buffers) > > > N=32 (no of connections) > > > in postmaster.opt which I take it is the equivalent of the new > > > postgresql.conf file. > > > > > > From all that is being written about later versions I suspect > > > that this is far too low. Would I be fairly safe in making the > > > no of shared buffers larger? Also is there an equivalent of > > > effective_cache_size that I can set for version 7? > > > > > > Many thanks in advance > > > Hilary > > > > > > > > > > > > > > > Hilary Forbes > > > ------------- > > > DMR Computer Limited: http://www.dmr.co.uk/ > > > Direct line: 01689 889950 > > > Switchboard: (44) 1689 860000 Fax: (44) 1689 860330 > > > E-mail: [EMAIL PROTECTED] > > > > > > ********************************************************** > > > > > > > > > ---------------------------(end of > broadcast)--------------------------- > > > TIP 5: Have you checked our extensive FAQ? > > > > > > http://www.postgresql.org/docs/faqs/FAQ.html > > > > > > > > > > > ---------------------------(end of broadcast)--------------------------- > > TIP 5: Have you checked our extensive FAQ? > > > > http://www.postgresql.org/docs/faqs/FAQ.html > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 6: Have you searched our list archives? > > http://archives.postgresql.org ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
