From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | Andrew Sullivan <andrew(at)libertyrms(dot)info> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: Tuning for mid-size server |
Date: | 2003-12-14 05:42:21 |
Message-ID: | 200312140542.hBE5gLI21410@candle.pha.pa.us |
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Lists: | pgsql-performance |
Andrew Sullivan wrote:
> On Tue, Oct 21, 2003 at 03:11:17PM -0600, scott.marlowe wrote:
> > I think where it makes sense is when you have something like a report
> > server where the result sets may be huge, but the parellel load is load,
> > i.e. 5 or 10 users tossing around 100 Meg or more at time.
>
> In our case, we were noticing that truss showed an unbelievable
> amount of time spent by the postmaster doing open() calls to the OS
> (this was on Solaris 7). So we thought, "Let's try a 2G buffer
> size." 2G was more than enough to hold the entire data set under
> question. Once the buffer started to fill, even plain SELECTs
> started taking a long time. The buffer algorithm is just not that
> clever, was my conclusion.
>
> (Standard disclaimer: not a long, controlled test. It's just a bit
> of gossip.)
I know this is an old email, but have you tested larger shared buffers
in CVS HEAD with Jan's new cache replacement policy?
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
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+ Christ can be your backup. | Newtown Square, Pennsylvania 19073
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