Re: 7k records into Sort node, 4.5m out? - Mailing list pgsql-performance

From Tom Lane
Subject Re: 7k records into Sort node, 4.5m out?
Date
Msg-id 16268.1345063872@sss.pgh.pa.us
Whole thread Raw
In response to Re: 7k records into Sort node, 4.5m out?  (Christophe Pettus <xof@thebuild.com>)
Responses Re: 7k records into Sort node, 4.5m out?  (Josh Berkus <josh@agliodbs.com>)
List pgsql-performance
Christophe Pettus <xof@thebuild.com> writes:
> On Aug 13, 2012, at 7:11 PM, Tom Lane wrote:
>> The whole thing looks a bit weird to me --- why did it not use a
>> nestloop join with inner indexscan on charlie?  With 7000 rows on the
>> other side, the estimated cost for that shouldn't have been more than
>> about 30000 ...

> Here's the same query with set enable_megejoin = off.  All of the other query tuning parameters are default.

>     http://explain.depesz.com/s/dqO

Maybe you had better show us the actual query, and the table/index
definitions.  Because it's sure making odd choices here.  This seems
like the wrong join order altogether ...

            regards, tom lane


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