Re: Index not used with or condition
От | Jan Poslusny |
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Тема | Re: Index not used with or condition |
Дата | |
Msg-id | 420756BA.4080507@gingerall.cz обсуждение исходный текст |
Ответ на | Re: Index not used with or condition (Antony Paul <antonypaul24@gmail.com>) |
Ответы |
Re: Index not used with or condition
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Список | pgsql-performance |
It depends on many circumstances, but, at first, simple question: Did you run vacuum analyze? I am satisfied with functional indexes - it works in my pg 7.4.x. Antony Paul wrote: >On more investigation I found that index scan is not used if the query >have a function in it like lower() and an index exist for lower() >column. > >rgds >Antony Paul > > >On Mon, 7 Feb 2005 14:37:15 +0530, Antony Paul <antonypaul24@gmail.com> wrote: > > >>Hi all, >> I am facing a strange problem when I run EXPLAIN against a table >>having more than 100000 records. The query have lot of OR conditions >>and when parts of the query is removed it is using index. To analyse >>it I created a table with a single column, inserted 100000 >>records(random number) in it created index and run a query which >>returns 1 record which have no or condition and it was using index. I >>added an OR conditon and is using sequential scan. I set the >>enable_seqscan to off. I ran the tests again and is using index scan. >> So which one I have to use. Is this any bug in Explain. >> >>rgds >>Antony Paul. >> >> >> > >---------------------------(end of broadcast)--------------------------- >TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to majordomo@postgresql.org so that your > message can get through to the mailing list cleanly > > >
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