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Re: Index on a NULL-value

From: Bruno Wolff III <bruno(at)wolff(dot)to>
To: Tobias Brox <tobias(at)nordicbet(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Index on a NULL-value
Date: 2005-05-31 04:08:01
Message-ID: 20050531040801.GA21334@wolff.to (view raw or flat)
Thread:
Lists: pgsql-performance
On Tue, May 31, 2005 at 11:31:58 +0800,
  Tobias Brox <tobias(at)nordicbet(dot)com> wrote:
> [Tobias Brox]
> > test=# set enable_seqscan=off; 
> 
> [Bruno Wolff III - Mon at 10:16:53PM -0500]
> > It isn't surprising that an index wasn't used since a sequential scan is
> > going to be faster in your test case.
> > 
> > If you want to test this out, you to want use realistically sized tables.
> 
> Wrong.  In this case I was not wondering about the planners choise of not
> using the index, but the fact that the planner could not find the index at
> all.  Reproducing it on a simple table in a test environment was a valid
> strategy to solve this specific problem.

I missed that you turned sequential scans off for your test.

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