Re: tuplesort.c's copytup_index() is dead code

On Thu, Jun 23, 2016 at 7:59 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I think this may be premature in view of bug #14210.  Even if we
> don't reinstate use of this function to fix that, I'm not really
> convinced we want to get rid of it; it seems likely to me that
> we might want it again.

Oh, yes; that involves the same commit I mentioned. I'll look into #14210.

FWIW, I think that that bug tells us a lot about hash index usage in
the field. It took many months for someone to complain about what
ought to have been a really obvious bug. Clearly, hardly anybody is
using hash indexes. I broke hash index tuplesort builds in a similar
way at one point, too. The slightest bit of regression test coverage
would have caught either bug, I believe. I think that some minimal
regression tests should be added, because evidently they are needed.

-- 
Peter Geoghegan