From: Josh Berkus <josh@agliodbs.com>
To: pgsql-performance@postgresql.org
Cc: Michael Stone <mstone+postgres@mathom.us>
Subject: Re: PG8 Tuning
Date: Wed, 17 Aug 2005 13:39:47 -0700
Message-ID: <200508171339.47399.josh@agliodbs.com> (raw)
In-Reply-To: <20050816173047.GC19080@mathom.us>
References: <1536.217.45.209.171.1123763001.squirrel@www.gradwell.com>
<200508160912.32263.josh@agliodbs.com>
<20050816173047.GC19080@mathom.us>
Michael,
> Well, you don't have to spend *quite* that much to get a decent storage
> array. :)
Yes, I'm just pointing out that it's only the extreme cases which are
clear-cut. Middle cases are a lot harder to define. For example, we've
found that on DBT2 running of a 14-drive JBOD, seperating off WAL boosts
performance about 8% to 14%. On DBT3 (DSS) seperate WAL (and seperate
tablespaces) helps considerably during data load,but not otherwise. So it
all depends.
> That's a different creature from
> a data mining app that might really benefit from having additional
> spindles to accelerate read performance from indices much larger than
> RAM.
Yes, although the data mining app benefits from the special xlog disk
during ETL. So it's a tradeoff.
> At any rate, this just underscores the need for testing a
> particular workload on particular hardware
Yes, absolutely.
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco
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To: pgsql-performance@postgresql.org
Cc: josh@agliodbs.com, mstone+postgres@mathom.us
Subject: Re: PG8 Tuning
In-Reply-To: <200508171339.47399.josh@agliodbs.com>
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