From: Tom Lane <tgl@sss.pgh.pa.us>
To: Kishore B <kishorebh@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Why Index is not working on date columns.
Date: Tue, 25 Oct 2005 09:38:35 -0400
Message-ID: <13279.1130247515@sss.pgh.pa.us> (raw)
In-Reply-To: <42567e060510250147j582ce648p3ceef8e4376975be@mail.gmail.com>
References: <42567e060510250147j582ce648p3ceef8e4376975be@mail.gmail.com>
Kishore B <kishorebh@gmail.com> writes:
> Can you guys please take a look at the following query and let me know why
> the index is not considered in the plan?
"Considered" and "used" are two different things.
The two examples you give have the same estimated cost (within two
decimal places) so the planner sees no particular reason to choose one
over the other.
I surmise that you are testing on toy tables and extrapolating to what
will happen on larger tables. This is an unjustified assumption.
Create a realistic test data set, ANALYZE it, and then see if the
planner chooses indexes you like.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, kishorebh@gmail.com
Subject: Re: Why Index is not working on date columns.
In-Reply-To: <13279.1130247515@sss.pgh.pa.us>
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