Re: [GENERAL] Estimated rows question - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [GENERAL] Estimated rows question
Date
Msg-id 6242.1347491946@sss.pgh.pa.us
Whole thread Raw
In response to Re: [GENERAL] Estimated rows question  (Sam Ross <elliptic@gmail.com>)
Responses Re: [GENERAL] Estimated rows question  (David Fetter <david@fetter.org>)
List pgsql-hackers
Sam Ross <elliptic@gmail.com> writes:
> On Sat, Sep 1, 2012 at 8:47 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Do you want to try it and submit a patch for testing?

> Thanks for the answer, and sorry for the slow reply -
> I'm not sure I have the necessary expertise, but I'll be happy to give
> it a shot.  Is there an already-assembled library of queries that is
> used to test purported improvements to the planner, or is it expected
> that I come up with a convincing test-set myself?

No, we don't really have much in that line :-(.  There's the regression
tests of course, but they're mostly about functionality not quality of
statistical estimates.  In practice, as long as a proposed change made
the estimates demonstrably better in some reasonable scenarios, and
didn't slow it down very much, that would probably be enough.
        regards, tom lane



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