Re: pgsql: Do execGrouping.c via expression eval machinery.

On 2018-02-15 22:14:30 -0800, Andres Freund wrote:
> On 2018-02-16 05:58:09 +0000, Andres Freund wrote:
> > Do execGrouping.c via expression eval machinery.
> > 
> > This has a performance benefit on own, although not hugely so. The
> > primary benefit is that it will allow for to JIT tuple deforming and
> > comparator invocations.
> > 
> > Author: Andres Freund
> > Discussion: https://postgr.es/m/20171129080934.amqqkke2zjtekd4t@alap3.anarazel.de
> 
> Triggered a failure on termite:
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=termite&dt=2018-02-16%2006%3A00%3A06
> investigating. If I can't figure this out by tomorrow PST morning, I'll
> revert.

I've analyzed the problem - the cross type case isn't quite right
(i.e. the FindTupleHashEntry call in nodeSubplan.c). Unfortunately we do
not exercise that code in a meaningful manner on a 64 bit system, as
int4 vs int8 is nearly invisible there...  Reverting as writing a fix
and developing appropriate coverage will take a couple hours.

Greetings,

Andres Freund