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Re: 8.4.7, incorrect estimate

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: "Wayne Conrad" <wayne(at)databill(dot)com>, <pgsql-performance(at)postgresql(dot)org>
Subject: Re: 8.4.7, incorrect estimate
Date: 2011-04-29 19:12:44
Message-ID: 4DBAC75C020000250003D06B@gw.wicourts.gov (view raw or flat)
Thread:
Lists: pgsql-performance
Wayne Conrad <wayne(at)databill(dot)com> wrote:
 
> select page_number, ps_id, ps_page_id from ps_page where
> ps_page_id in (select ps_page_id from documents_ps_page where
> document_id in (select document_id from temp_doc_ids)) order by
> ps_page_id;
 
> [estimated rows=34398932; actual rows=5]
 
> We tried increasing (from 100 to 1,000 and 10,000) the statistics
> targets for each of the indexed columns, one at a time, and
> analyzing the table/column with each change.  This had no effect
 
Ouch.
 
Out of curiosity, what do you get with?:
 
explain analyze
select
    page_number,
    ps_id,
    ps_page_id
  from ps_page p
  where exists
        (
          select * from documents_ps_page d
            where d.ps_page_id = p.ps_page_id
              and exists
                  (select * from temp_document_ids t
                     where t.document_id = d.document_id)
        )
  order by ps_page_id
;
 
-Kevin

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