| From: | Dirk(dot)Lutzebaeck(at)t-online(dot)de (Dirk Lutzebaeck) |
|---|---|
| To: | John A Meinel <john(at)arbash-meinel(dot)com> |
| Cc: | Greg Stark <gsstark(at)mit(dot)edu>, pgsql-performance(at)postgresql(dot)org, tgl(at)sss(dot)pgh(dot)pa(dot)us |
| Subject: | Re: query produces 1 GB temp file |
| Date: | 2005-02-06 16:04:05 |
| Message-ID: | 42063FF5.9040707@aeccom.com |
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| 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
> =:->
>
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