From: Josh Berkus <josh@agliodbs.com>
To: pgsql-performance@postgresql.org
Cc: Steve Poe <spoe@sfnet.cc>
Cc: Chris Browne <cbbrowne@acm.org>
Subject: Re: Read/Write block sizes
Date: Tue, 23 Aug 2005 19:31:29 -0700
Message-ID: <200508231931.29682.josh@agliodbs.com> (raw)
In-Reply-To: <1124846743.12045.94.camel@amd64-laptop-spoe>
References: <d4b67d7c2b.d7c2bd4b67@bur-mail1.east.sun.com>
<60k6icpapm.fsf@dba2.int.libertyrms.com>
<1124846743.12045.94.camel@amd64-laptop-spoe>
Steve,
> I would assume that dbt2 with STP helps minimize the amount of hours
> someone has to invest to determine performance gains with configurable
> options?
Actually, these I/O operation issues show up mainly with DW workloads, so the
STP isn't much use there. If I can ever get some of these machines back
from the build people, I'd like to start testing some stuff.
One issue with testing this is that currently PostgreSQL doesn't support block
sizes above 128K. We've already done testing on that (well, Mark has) and
the performance gains aren't even worth the hassle of remembering you're on a
different block size (like, +4%).
What the Sun people have done with other DB systems is show that substantial
performance gains are possible on large databases (>100G) using block sizes
of 1MB. I believe that's possible (and that it probably makes more of a
difference on Solaris than on BSD) but we can't test it without some hackery
first.
--
Josh Berkus
Aglio Database Solutions
San Francisco
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To: pgsql-performance@postgresql.org
Cc: josh@agliodbs.com, spoe@sfnet.cc, cbbrowne@acm.org
Subject: Re: Read/Write block sizes
In-Reply-To: <200508231931.29682.josh@agliodbs.com>
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