Re: Query performance - normal on 9.0.4, slow from 9.0.5 onwards

From: Miguel Silva <miguel(dot)silva(at)tactis(dot)pt>
To: Merlin Moncure <mmoncure(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Query performance - normal on 9.0.4, slow from 9.0.5 onwards
Date: 2012-01-02 11:44:43
Message-ID: 4F0198AB.6030405@tactis.pt
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On 30-12-2011 19:35, Merlin Moncure wrote:
> try this (curious):
> create table pos as select n from generate_series(1,32) n;
>
> and swap that for the in-query generate series call. your statistics
> in the query are completely off (not 100% sure why), so I'm thinking
> to replace that since it lies to the planner about the # rows
> returned. also the join on the array element probably isn't helping.
>
> merlin
>
Tried it. The query still takes around the same amount of time but, out
of curiosity, here's the explain analyze of it:
http://explain.depesz.com/s/MvE .

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