Re: Index not used with or condition

From: Antony Paul <antonypaul24(at)gmail(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Index not used with or condition
Date: 2005-02-07 11:14:07
Message-ID: 2989532e0502070314402057cc@mail.gmail.com
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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(at)gmail(dot)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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