Re: Slow query using simple equality operators

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От Benjamin Arai
Тема Re: Slow query using simple equality operators
Дата
Msg-id F3244B6B-3700-4362-BCB2-8B28F4EA6395@araisoft.com
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Ответ на Slow query using simple equality operators  (Benjamin Arai <benjamin@araisoft.com>)
Ответы Re: Slow query using simple equality operators
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To follow up on my own email, by disabling BitmapScan in my
postgresql.conf the performance seems to be better. Is something
wrong with the query analyzer?

v=# explain select s_content,textdir from text_search where
path_id='1' AND tb_id='P2_TB00001';
                                            QUERY PLAN
------------------------------------------------------------------------
------------------------
Index Scan using idx_search_path_id on text_search
(cost=0.00..4081857.23 rows=5083 width=36)
    Index Cond: (path_id = 1)
    Filter: (tb_id = 'P2_TB00001'::text)
(3 rows)

Benjamin

On Apr 23, 2007, at 3:38 PM, Benjamin Arai wrote:

> Can anybody explain to me why this query is executing so slow?
>
> =# explain select s_content,textdir from text_search where
> path_id='1' AND tb_id='P2_TB00001';
>                                            QUERY PLAN
> ----------------------------------------------------------------------
> ---------------------------
> Bitmap Heap Scan on text_search  (cost=39861.94..59743.55 rows=5083
> width=36)
>    Recheck Cond: ((path_id = 1) AND (tb_id = 'P2_TB00001'::text))
>    ->  BitmapAnd  (cost=39861.94..39861.94 rows=5083 width=0)
>          ->  Bitmap Index Scan on idx_search_path_id
> (cost=0.00..16546.09 rows=1016571 width=0)
>                Index Cond: (path_id = 1)
>          ->  Bitmap Index Scan on idx_search_tb_id
> (cost=0.00..23315.60 rows=1016571 width=0)
>                Index Cond: (tb_id = 'P2_TB00001'::text)
> (7 rows)
>
> Thanks in advance!
>
> Benjamin
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 5: don't forget to increase your free space map settings
>


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