Re: "could not find pathkey item to sort" for TPC-DS queries 94-96

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: James Coleman <jtc331@gmail.com>
Cc: Tomas Vondra <tomas.vondra@enterprisedb.com>, Luc Vlaming <luc@swarm64.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>
Date: 2021-04-19T21:37:50Z
Lists: pgsql-hackers
James Coleman <jtc331@gmail.com> writes:
> I forgot to comment on this in my previous email, but it seems to me
> that relation_has_safe_ec_member, while less wordy, isn't quite
> descriptive enough. Perhaps something like
> relation_has_sort_safe_ec_member?

I'm not wedded to that name, certainly, but it seems like neither
of these is quite getting at the issue.  An EC can be sorted on,
by definition, but there are some things we don't want to sort
on till the final output step.  I was trying to think of something
using the terminology "early sort", but didn't much like
"relation_has_early_sortable_ec_member" or obvious variants of that.

			regards, tom lane



Commits

  1. Rename find_em_expr_usable_for_sorting_rel.

  2. Fix planner failure in some cases of sorting by an aggregate.