Re: idea for concurrent seqscans

On Fri, 2005-02-25 at 18:03 -0600, Jim C. Nasby wrote:
> On Fri, Feb 25, 2005 at 01:30:57PM -0500, Tom Lane wrote:
> > Jeff Davis <jdavis-pgsql(at)empires(dot)org> writes:
> > > I didn't consider that. Is there a reason the regression tests assume
> > > the results will be returned in a certain order (or a consistent order)?
> >
> > We use diff as the checking tool.
>
> Doesn't the SQL spec specifically state that the only time you'll get
> results in a deterministic order is if you use ORDER BY? Assuming
> otherwise seems a bad idea (though at least in the case of testing it
> makes the test more strenuous rather than less...)

True, that was my reasoning when I proposed synchronized scanning.

Keep in mind that this is a criticism of only the regression tests, not
the RDBMS itself.

I don't know much about the regression tests, so maybe it's impractical
to not assume consistent order. I'm sure the developers will vote one
way or the other. I hate to throw away a potential performance boost,
but I also hate to burden the developers with rewriting a lot of
regression tests when their time could be better spent elsewhere.

Regards,
Jeff Davis