From: Josh Berkus <josh@agliodbs.com>
To: Joe Conway <mail@joeconway.com>
To: pgsql-sql@postgresql.org
Subject: Re: Hardware performance for large updates
Date: Fri, 06 Sep 2002 09:10:26 -0700
Message-ID: <web-1635967@davinci.ethosmedia.com> (raw)
In-Reply-To: <3D78300C.7030403@joeconway.com>
Joe,
> I think we'd need more information to be of any help -- schema,
> functions, explain output, etc.
Yeah, I know. I'm just looking for general tips here ... I need to do
the actual optimization interactively.
Particularly, the difficulty is that this application gets many small
requests during the day (100 simultaneous uses) and shares a server
with Apache. So I have to be concerned about how much memory each
connection soaks up, during the day. At night, the maintainence tasks
run a few, really massive procedures.
So I should probably restart Postgres with different settings at night,
hey?
> I do think you probably could increase Shared Buffers, as 256 is
> pretty small. There's been a lot of debate over the best setting. The
> usual guidance is start at 25% of physical RAM (16384 == 128MB if you
> have 512MB RAM), then tweak to optimize performance for your
> application and hardware.
Hmmm... how big is a shared buffer, anyway? I'm having trouble
finding actual numbers in the docs.
> You might also bump sort mem up a bit
> (maybe to 2048). Again, I would test using my app and hardware to get
> the best value.
> Are you on a Linux server -- if so I found that
> fdatasync works better than (the default) fsync for wal_sync_method.
Yes, I am. Any particular reason why fdatasync works better?
Thanks a lot!
-Josh Berkus
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To: pgsql-sql@postgresql.org
Cc: josh@agliodbs.com, mail@joeconway.com
Subject: Re: Hardware performance for large updates
In-Reply-To: <web-1635967@davinci.ethosmedia.com>
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