Re: The old "not using index" question
От | Jan-Philipp 'Thefly' Reining |
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Тема | Re: The old "not using index" question |
Дата | |
Msg-id | 045801c29a02$3c6f3b90$84c206d4@thefly обсуждение исходный текст |
Ответ на | The old "not using index" question ("Jan-Philipp 'Thefly' Reining" <jpr@turtle-entertainment.de>) |
Ответы |
Re: The old "not using index" question
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Список | pgsql-general |
Hi there, > show us explain analyze output. Here we go: ---this one is using the index on "ranking" SELECT * FROM ttm_slots s WHERE s.peering = 72 AND s.ranking = 1050 explain: Index Scan using ranking_ttm_slots_key on ttm_slots s (cost=0.00..191.06 rows=8 width=62) ---but this one does not? SELECT * FROM ttm_slots s WHERE s.peering = 72 AND s.ranking < 1050 AND s.ranking > 950 explain: Seq Scan on ttm_slots s (cost=0.00..1823.64 rows=7949 width=62) The index ist "btree", so it should be able to use the index with a < > comparison? \d ranking_ttm_slots_key Index "ranking_ttm_slots_key" Column | Type ---------+--------- ranking | integer btree regards, // Jan-Philipp 'Thefly' Reining ----- Original Message ----- From: "Hubert depesz Lubaczewski" <depesz@depesz.pl> To: "Jan-Philipp 'Thefly' Reining" <jpr@turtle-entertainment.de>; <pgsql-general@postgresql.org> Sent: Saturday, November 30, 2002 1:20 AM Subject: Re: [GENERAL] The old "not using index" question > On Fri, Nov 29, 2002 at 05:37:04PM +0100, Jan-Philipp 'Thefly' Reining wrote: > > ---but this one does not? > > SELECT * > > FROM ttm_slots s > > WHERE s.peering = 72 > > AND s.ranking < 1050 > > AND s.ranking > 950 > > > > The index ist "btree", so it should be able to use the index with a < > > > comparison? > > show us explain analyze output. > probably planner thinks there are too many rows matching this criteria > to use index. > > depesz > > -- > hubert depesz lubaczewski http://www.depesz.pl/ > ------------------------------------------------------------------------ > Mój Boże, spraw abym milczał, dopóki się nie upewnię, że naprawdę mam > coś do powiedzenia. (c) 1998 depesz > >
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