Re: ways to force index use?

From: Gaetano Mendola <mendola(at)bigfoot(dot)com>
To: "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: ways to force index use?
Date: 2003-10-14 00:20:40
Message-ID: 3F8B4158.2030600@bigfoot.com
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Tom Lane wrote:
> Seth Ladd <seth(at)picklematrix(dot)net> writes:
>
>>My Table Columns (all bigints): start, stop, step1, step2, step3
>
> ^^^^^^^^^^^
>
>
>>The Query: explain analyze select * from path where start = 653873 or
>>start = 649967 or stop = 653873 or stop = 649967
>
>
>>Does anyone have a suggestion on how to get that query to use an index?
>
>
> Coerce the constants to bigint, for starters. However, a query that is
> selecting almost 10% of the table, as your example is, probably
> *shouldn't* be using an index.

I think that for 10% is still better and Index scan.
There is around a way to calculate this elbow ?

Regards
Gaetano Mendola

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