Re: Another optimizer question

From: Dennis Haney <davh(at)diku(dot)dk>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Another optimizer question
Date: 2004-01-27 19:08:58
Message-ID: 4016B74A.2010907@diku.dk
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Tom Lane wrote:

>Dennis Haney <davh(at)diku(dot)dk> writes:
>
>
>>There is no constraint on the order of 'a', so why is pull_up_subqueries
>>explicitly ignoring subqueries that contain an 'order by'?
>>
>>
>
>Because there would be no place to apply the sort operation.
>
Then why spend time doing it at all?

> If you are saying you don't want the sort to occur,
>
>
I'm saying the sort makes no sense. So why even bother executing it?

> why did you write it?
>
I believe the most common scenario would be that the subquery was
expanded from a view...

--
Dennis

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