From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | Josh Berkus <josh(at)agliodbs(dot)com> |
Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Was partitioned table row estimation fixed in 9.0? |
Date: | 2010-02-27 03:00:09 |
Message-ID: | 11001.1267239609@sss.pgh.pa.us |
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Lists: | pgsql-hackers |
Josh Berkus <josh(at)agliodbs(dot)com> writes:
> There were a flurry of patches around this from Stark and Aster Data, so
> I'm checking if I should be testing on 9.0 or adding this to the TODO list.
> The problem I'm grappling with is that OUTER JOINS against the master in
> a partitioned table (joining to the append node) gives a row estimate
> which does not take into account any CE applicable to the partitioned
> table. The CE is properly executed when the join is actually executed,
> but with the row estimate way off (orders of magnitude) you often get
> bad plans for other joins in the query.
Would you give a concrete example? There was some work done in this
area but it's impossible to tell whether it solves your problem with
only that much detail.
regards, tom lane
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