Re: PostgreSQL settings for running on an SSD drive

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: sthomas(at)optionshouse(dot)com
Cc: Josh Berkus <josh(at)agliodbs(dot)com>, pgsql-performance(at)postgresql(dot)org, Greg Smith <greg(at)2ndQuadrant(dot)com>
Subject: Re: PostgreSQL settings for running on an SSD drive
Date: 2013-06-20 21:32:34
Message-ID: 51C374F2.4050208@dunslane.net
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance


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

In response to

Browse pgsql-performance by date

  From Date Subject
Next Message Maciek Sakrejda 2013-06-21 01:24:46 Query tuning: partitioning, DISTINCT ON, and indexing
Previous Message Shaun Thomas 2013-06-20 21:23:06 Re: PostgreSQL settings for running on an SSD drive