Horton

Re: query produces 1 GB temp file

Dirk Lutzebaeck <dirk.lutzebaeck@t-online.de>

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From: Dirk.Lutzebaeck@t-online.de (Dirk Lutzebaeck)
To: John A Meinel <john@arbash-meinel.com>
Cc: Greg Stark <gsstark@mit.edu>, pgsql-performance@postgresql.org, tgl@sss.pgh.pa.us
Date: 2005-02-06T16:04:05Z
Lists: pgsql-performance 
John,

I'm doing VACUUM ANALYZE once a night. Before the tests I did VACUUM and 
then ANALYZE.

Dirk

John A Meinel wrote:

> Dirk Lutzebaeck wrote:
>
>> Greg,
>>
>> Thanks for your analysis. But I dont get any better after bumping 
>> STATISTICS target from 10 to 200.
>> explain analyze shows that the optimizer is still way off estimating 
>> the rows. Is this normal? It still produces a 1 GB temp file.
>> I simplified the query a bit, now only two tables are involved (bi, 
>> df). I also vacuumed.
>
>
>
> Are you just doing VACUUM? Or are you doing VACUUM ANALYZE? You might 
> also try VACUUM ANALYZE FULL (in the case that you have too many dead 
> tuples in the table).
>
> VACUUM cleans up, but doesn't adjust any planner statistics without 
> ANALYZE.
>
> John
> =:->
>