From: Greg Smith <greg@2ndquadrant.com>
To: Brad Nicholson <bnichols@ca.afilias.info>
Cc: Scott Carey <scott@richrelevance.com>
Cc: Michael March <mmarch@gmail.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Completely un-tuned Postgresql benchmark results: SSD vs desktop HDD
Date: Tue, 10 Aug 2010 14:28:31 -0400
Message-ID: <4C619A4F.7080306@2ndquadrant.com> (raw)
In-Reply-To: <4C619300.3080400@ca.afilias.info>
References: <AANLkTikXLYc32Jyr5Fb8VeVNt6R86mCcF+0CkTHALd8W@mail.gmail.com>
<BAE01AAD-6C69-48C7-BD2E-77E463D49903@richrelevance.com>
<AANLkTi=km+H+mZ=yyx0_HTFZ-yU2sh85D+p5cs+ZcUSF@mail.gmail.com>
<A1640F99-A7C5-4F04-9A25-782C46BE7DAB@richrelevance.com>
<4C617C80.9080509@2ndquadrant.com>
<4C619300.3080400@ca.afilias.info>
Brad Nicholson wrote:
> What about putting indexes on them? If the drive fails and drops
> writes on those, they could be rebuilt - assuming your system can
> function without the index(es) temporarily.
Dumping indexes on SSD is one of the better uses for them, presuming you
can survive what is likely to be an outage from a "can the site handle
full load?" perspective while they rebuild after a crash. As I'm sure
Brad is painfully aware of already, index rebuilding in PostgreSQL can
take a while. To spin my broken record here again, the main thing to
note when you consider that--relocate indexes onto SSD--is that the ones
you are most concerned about the performance of were likely to be
already sitting in RAM anyway, meaning the SSD speedup doesn't help
reads much. So the giant performance boost just isn't there in that case.
--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com www.2ndQuadrant.us
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To: pgsql-performance@postgresql.org
Cc: greg@2ndquadrant.com, bnichols@ca.afilias.info, scott@richrelevance.com, mmarch@gmail.com
Subject: Re: Completely un-tuned Postgresql benchmark results: SSD vs desktop HDD
In-Reply-To: <4C619A4F.7080306@2ndquadrant.com>
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