From: Andrew Dunstan <andrew@dunslane.net>
To: sthomas@optionshouse.com
Cc: Josh Berkus <josh@agliodbs.com>
Cc: pgsql-performance@postgresql.org, Greg Smith <greg@2ndQuadrant.com>
Subject: Re: PostgreSQL settings for running on an SSD drive
Date: Thu, 20 Jun 2013 17:32:34 -0400
Message-ID: <51C374F2.4050208@dunslane.net> (raw)
In-Reply-To: <51C372BA.1040807@optionshouse.com>
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On 06/20/2013 05:23 PM, Shaun Thomas wrote:
> On 06/20/2013 03:32 PM, Josh Berkus wrote:
>
>> Did you compare setting RPC to 1.0 vs. setting it to 1.1, or something
>> else just slightly higher than SPC?
>
> Yes, actually. My favored setting when we were on 8.3 was 1.5. But
> something with the planner changed pretty drastically when we went to
> 9.1, and we were getting some really bad query plans unless we
> *strongly* suggested RPC was cheap. I was afraid I'd have to go lower,
> but 1 seemed to do the trick.
>
That would be perverse, surely, but on Fusion-IO RPC = SPC seems to make
sense unless you assume that cache misses will be higher for random
reads than for sequential reads.
cheers
andrew
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To: pgsql-performance@postgresql.org
Cc: andrew@dunslane.net, sthomas@optionshouse.com, josh@agliodbs.com, greg@2ndQuadrant.com
Subject: Re: PostgreSQL settings for running on an SSD drive
In-Reply-To: <51C374F2.4050208@dunslane.net>
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