Re: 7k records into Sort node, 4.5m out?

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От Josh Berkus
Тема Re: 7k records into Sort node, 4.5m out?
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Msg-id 502C0E6B.1040402@agliodbs.com
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Ответ на Re: 7k records into Sort node, 4.5m out?  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: 7k records into Sort node, 4.5m out?  (Tom Lane <tgl@sss.pgh.pa.us>)
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On 8/15/12 1:51 PM, Tom Lane wrote:
> 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 ...

We'll need to do that off-list for confidentiality reasons.


--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com


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