From: Greg Sabino Mullane <greg@turnstep.com>
To: pgsql-performance@postgresql.org
Cc: Scott Marlowe <scott.marlowe@gmail.com>
Cc: Josh Berkus <josh@agliodbs.com>
Cc: Marcos Ortiz Valmaseda <mlortiz@uci.cu>
Subject: Re: random_page_cost = 2.0 on Heroku Postgres
Date: Thu, 9 Feb 2012 04:39:50 -0000
Message-ID: <00198dd656e4228cb66aa53a68ca0e14@biglumber.com> (raw)
In-Reply-To: <4F3329DF.2060805@uci.cu>
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> You can execute several queries with the three different values provided
> by Scott and Josh.
> - SET random_page_cost = 2.0
> First execution of the queries with EXPLAIN ANALYZE
> - SET random_page_cost = 1.4
> Second execution of the queries with EXPLAIN ANALYZE
> - SET random_page_cost = 1.2
> Second execution of the queries with EXPLAIN ANALYZE
Well, such a tool would ideally be smarter than that, such that
you would run EXPLAIN and compare to the previous plan and
only run EXPLAIN ANALYZE if the plan changed. One could even
decrement rpc slowly and find out at one points it changes,
which would be more interesting than testing arbitrary numbers.
Would lead to some really sweet graphs as well. :)
- --
Greg Sabino Mullane greg@turnstep.com
End Point Corporation http://www.endpoint.com/
PGP Key: 0x14964AC8 201202082338
http://biglumber.com/x/web?pk=2529DF6AB8F79407E94445B4BC9B906714964AC8
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To: pgsql-performance@postgresql.org
Cc: greg@turnstep.com, scott.marlowe@gmail.com, josh@agliodbs.com, mlortiz@uci.cu
Subject: Re: random_page_cost = 2.0 on Heroku Postgres
In-Reply-To: <00198dd656e4228cb66aa53a68ca0e14@biglumber.com>
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