Re: Index not used with or condition

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От Jan Poslusny
Тема Re: Index not used with or condition
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Msg-id 420756BA.4080507@gingerall.cz
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Ответ на Re: Index not used with or condition  (Antony Paul <antonypaul24@gmail.com>)
Ответы Re: Index not used with or condition  (Antony Paul <antonypaul24@gmail.com>)
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.
>>
>>
>>
>
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