Re: idea for concurrent seqscans

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
Cc: Jeff Davis <jdavis-pgsql(at)empires(dot)org>, Simon Riggs <simon(at)2ndquadrant(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: idea for concurrent seqscans
Date: 2005-02-26 15:47:52
Message-ID: 21739.1109432872@sss.pgh.pa.us
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"Jim C. Nasby" <decibel(at)decibel(dot)org> writes:
> Assuming you're talkning about "You might wonder why we don't order all
> the regression test queries explicitly to get rid of this issue once and
> for all. The reason is that that would make the regression tests less
> useful, not more, since they'd tend to exercise query plan types that
> produce ordered results to the exclusion of those that don't.", good
> point. I can think of 2 ways around this:

> 1) Select into a temptable, then select out of it with an order by

> 2) Run the output through sort before doing the diff

> Is there any reason one of these wouldn't work?

Like I said originally, we could certainly devise a solution if we
needed to. I was just pointing out that this is a nontrivial
consideration, and I don't want to buy into it if the patch proves
to offer only marginal performance improvements.

regards, tom lane

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