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Re: Bad plan choice nestloop vs. hashjoin

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Kenneth Marshall <ktm(at)rice(dot)edu>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Bad plan choice nestloop vs. hashjoin
Date: 2010-01-16 00:27:27
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-performance
Kenneth Marshall <ktm(at)rice(dot)edu> writes:
> We have just upgraded our monitoring server software and
> now the following query for graphing the data performs
> abysmally with the default settings. Here is the results
> of the EXPLAIN ANALYZE run with nestloops enabled:

That plan seems a bit wacko --- I don't see a reason for it to be using
an indexscan on items ii.  Can you extract a self-contained test case?

			regards, tom lane

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