Re: Unexpected query plan results

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Anne Rosset <arosset(at)collab(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Unexpected query plan results
Date: 2009-06-01 20:24:10
Message-ID: 603c8f070906011324xf8ed743rfaf89ff21ddbf164@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

On Mon, Jun 1, 2009 at 2:14 PM, Anne Rosset <arosset(at)collab(dot)net> wrote:
>>> The table has 468173 rows and the value for default_statistics_target is
>>> 750.
>>> Anne
> Hi Robert,
> we did a vacuum analyze and the results are the same.
> Here are the results of the queries :
>
> SELECT SUM(1) FROM item WHERE is_deleted = 'f'; sum --------- 1824592 (1
> row)
> SELECT SUM(1) FROM item WHERE folder_id = 'tracker3641
> </sf/sfmain/do/go/tracker3641?returnUrlKey=1243878161701>'; sum --------
> 122412 (1 row)
> SELECT SUM(1) FROM item WHERE folder_id = 'tracker3641
> </sf/sfmain/do/go/tracker3641?returnUrlKey=1243878161701>' AND is_deleted =
> 'f'; sum ----- 71 (1 row)
> SELECT SUM(1) FROM item WHERE folder_id = 'tracker3641
> </sf/sfmain/do/go/tracker3641?returnUrlKey=1243878161701>' AND is_deleted =
> 't'; sum -------- 122341 (1 row)

Something's not right here. If the whole table has only 468173 rows,
you can't have 1.8 million deleted rows where is_deleted = false.

...Robert

In response to

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Anne Rosset 2009-06-01 20:53:24 Re: Unexpected query plan results
Previous Message Scott Carey 2009-06-01 19:19:44 Re: Scalability in postgres