Re: Scrollable cursors and Sort performance

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
Cc: Simon Riggs <simon(at)2ndquadrant(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Scrollable cursors and Sort performance
Date: 2006-02-27 23:01:21
Message-ID: 23047.1141081281@sss.pgh.pa.us
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"Jim C. Nasby" <jnasby(at)pervasive(dot)com> writes:
> On Mon, Feb 27, 2006 at 02:17:23PM +0000, Simon Riggs wrote:
>>> Possibly we could make EXPLAIN ANALYZE EXECUTE set the random-access
>>> bits.
>>
>> Good point. Whichever we do will be wrong in some cases.... I've no real
>> opinion on this other than a vague preference for it to be quick.

> Wouldn't an EXPLAIN ANALYZE DECLARE ... have the right information to
> know if backward scan, etc was needed?

There is no EXPLAIN ANALYZE DECLARE, and AFAICS it would be a
contradiction in terms to have one, since DECLARE doesn't run the query.
Perhaps the correct addition would be EXPLAIN ANALYZE FETCH. (EXECUTE
is unrelated, now that I think harder about it.)

regards, tom lane

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