Re: NOT IN Doesn't use Anti Joins?

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Rod Taylor <rod(dot)taylor(at)gmail(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: NOT IN Doesn't use Anti Joins?
Date: 2009-12-17 14:35:39
Message-ID: 603c8f070912170635m2c84212alffeea00ad35b26f6@mail.gmail.com
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On Thu, Dec 17, 2009 at 9:02 AM, Rod Taylor <rod(dot)taylor(at)gmail(dot)com> wrote:
> Is there a reason why the NOT IN plan could not use Anti-Joins when
> the column being compared against is guaranteed to be NOT NULL? Too
> much planner overhead to determine nullness of the column?

I doubt it. I think it's just a question of round tuits. I think Tom
hasn't felt it worth the effort since you can work around it by
rewriting the query, and nobody else has bothered to work up a patch.
If you feel like working on it, I think it would be a nice
improvement.

...Robert

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