Re: PG qsort vs. Solaris

Sorry. Stupid question. I didn't realize SQL allowed for the column
to be identified by number. I've never seen that before. :-)

Cheers,
mark

On Tue, Oct 03, 2006 at 06:47:35PM -0400, mark(at)mark(dot)mielke(dot)cc wrote:
> On Tue, Oct 03, 2006 at 03:44:38PM -0400, Tom Lane wrote:
> > select count(*) from
> > (select random()::text from generate_series(1,1000000) order by 1) ss;
> > ...
> > postgres=# select count(*) from (select random() from generate_series(1,1000000) order by 1) ss;
>
> I'm wondering whether 'order by 1' is representative of a real sort, from
> the perspective of benchmarks.
>
> I wonder why 'order by CONSTANT' might not be safe to optimize away as
> no sort at all?
>
> For sort functions that incrementally improve the sort order, I would
> expect 'order by 1' to be a worst case scenario. Is that the intention?
> Or is qsort unaffected by this use?

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