Re: Between Node - Mailing list pgsql-patches

From Tom Lane
Subject Re: Between Node
Date
Msg-id 4874.1026999590@sss.pgh.pa.us
Whole thread Raw
In response to Re: Between Node  (Rod Taylor <rbt@zort.ca>)
Responses Re: Between Node  (Rod Taylor <rbt@zort.ca>)
Re: Between Node  (Rod Taylor <rbt@zort.ca>)
List pgsql-patches
Rod Taylor <rbt@zort.ca> writes:
> On Thu, 2002-07-18 at 00:56, Christopher Kings-Lynne wrote:
>> I believe Tom mentioned that having BETWEEN as a node would allow him to do
>> some sort of funky optimiser improvement.  Is that already done or does he
>> still need to do it?

> I don't know what improvement this would be.  I only touched the parser
> and executor.

In that case, this code is worse than before as far as developing plans
goes.  The selectivity estimator needs to be taught about what BETWEEN
means.  Currently it recognizes (x > foo AND x < bar) as a range query
--- a BETWEEN node is obviously much easier to recognize, but you still
have to add code to do it.

            regards, tom lane

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