Re: idea for concurrent seqscans - Mailing list pgsql-hackers

From Tom Lane
Subject Re: idea for concurrent seqscans
Date
Msg-id 21739.1109432872@sss.pgh.pa.us
Whole thread Raw
In response to Re: idea for concurrent seqscans  ("Jim C. Nasby" <decibel@decibel.org>)
Responses Re: idea for concurrent seqscans  (Gaetano Mendola <mendola@bigfoot.com>)
Re: idea for concurrent seqscans  (Simon Riggs <simon@2ndquadrant.com>)
List pgsql-hackers
"Jim C. Nasby" <decibel@decibel.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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