From: Tom Lane <tgl@sss.pgh.pa.us>
To: uher dslij <codon3@gmail.com>
cc: pgsql-performance@postgresql.org
Subject: Re: Performance regressions in PG 9.3 vs PG 9.0
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Comments: In-reply-to uher dslij <codon3@gmail.com>
 message dated "Tue, 08 Apr 2014 15:58:52 -0400"
Date: Tue, 08 Apr 2014 17:26:37 -0400
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uher dslij <codon3@gmail.com> writes:
> The EXPLAINs all pretty much look like my original post.  The planner in
> 9.2 and above is simply not using bitmap heap scans or bitmap index scans?
>  What could be the reason for this?

I don't see any reason to think this is a planner regression.  The
rowcount estimates are pretty far off in both versions; so it's just a
matter of luck that 9.0 is choosing a better join order than 9.3.

I'd try cranking up the statistics targets for the join columns
(particularly domain_id) and see if that leads to better estimates.

			regards, tom lane


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