Re: Very inefficient query plan with disjunction in WHERE clause

From: Matthew Wakeling <matthew(at)flymine(dot)org>
To: Koen Martens <pgsql(at)metro(dot)cx>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Very inefficient query plan with disjunction in WHERE clause
Date: 2009-06-01 16:37:32
Message-ID: alpine.DEB.1.10.0906011736110.4147@aragorn.flymine.org
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On Mon, 1 Jun 2009, Koen Martens wrote:
> Anyway, any hints on getting this beast perform (without rewriting the
> query, that's not possible in this case due to the query being generated
> by an ORM) are welcome. I'm starting to think it is impossible, and that
> postgresql just doesn't work for this particular query+dataset.

Yeah, being bound by the ORM can be annoying. What version of Postgres is
this? Recent versions can sometimes do a bitmap index scan to satisfy an
OR constraint.

Matthew

--
Anyone who goes to a psychiatrist ought to have his head examined.

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