Re: add_path optimization - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: add_path optimization
Date
Msg-id 200902071944.n17JihP15254@momjian.us
Whole thread Raw
In response to Re: add_path optimization  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: add_path optimization
Re: add_path optimization
List pgsql-hackers
Robert Haas wrote:
> On Mon, Feb 2, 2009 at 8:10 PM, Kevin Grittner
> <Kevin.Grittner@wicourts.gov> wrote:
> >>>> Robert Haas <robertmhaas@gmail.com> wrote:
> >> running this 5 times each on several queries,
> >> dropping top and bottom results.
> >
> > Running a complex query (posted in previous threads, runs about
> > 300,000 time per day in a production web application), I got these
> > timings on a production quality machine (4 quad CPU chips, that is 16
> > CPUs like this: Intel(R) Xeon(R) CPU  X7350 @ 2.93GHz, 128 GB RAM, big
> > RAID with BBU).  I ran explain in each environment 5 times, tossed
> > high and low, and averaged.  The 8.4devel was from today's
> > (2008-02-02) snapshot, built the same way we did 8.3.5.
> >
> > 8.3.5, statistics target 10:  36.188 ms
> > 8.4devel without patch, statistics target 100:  109.862 ms
> > 8.4devel with patch, statistics target 100:  104.015 ms
> >
> > After seeing that, I re-analyzed to eliminate the statistics target as
> > the cause of the 8.4 increase.
> >
> > 8.4devel with patch, statistics target 10:  99.421 ms
> 
> Yikes!  The impact of the patch is about what I'd expect, but the fact
> that planning time has nearly tripled is... way poor.  Can you repost
> the query and the EXPLAIN output for 8.3.5 and CVS HEAD?

Where are we on this: the original patch, and Kevin's slow queries?

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +


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