Re: Inconsistent Behavior of GROUP BY ROLLUP in v17 vs master

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

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

To: Richard Guo <guofenglinux@gmail.com>

Cc: David Rowley <dgrowleyml@gmail.com>, 邱宇航 <iamqyh@gmail.com>, Bruce Momjian <bruce@momjian.us>, PostgreSQL-development <pgsql-hackers@postgresql.org>

Date: 2025-10-20T16:27:58Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Fix test case from 40c242830
- ee49f2cf447a 18.1 landed
Fix pushdown of degenerate HAVING clauses
- 40c2428307b8 18.1 landed
- 18d261409348 19 (unreleased) landed
Allow pushdown of HAVING clauses with grouping sets
- 67a54b9e83d3 18.0 cited
Mark expressions nullable by grouping sets
- f5050f795aea 18.0 cited

Attachments

v4-0001-Fix-pushdown-of-degenerate-HAVING-clauses.patch (text/x-diff) patch v4-0001

I wrote:
> I like the concept here, but not so much the details.  Pulling
> expand_grouping_sets out of preprocess_grouping_sets feels weird.
> I guess it's all right given that preprocess_grouping_sets doesn't
> manipulate the parse tree otherwise, but you didn't update the comment
> for preprocess_grouping_sets.  Also it might be a good idea to have a
> test case demonstrating why v2 wasn't good enough.

Here's a v4 with some concrete suggestions for comment changes,
plus the extra test case.  (I did some tiny cosmetic fooling with
preprocess_grouping_sets too, because the order of its initial
operations seemed quite weird to me.)

			regards, tom lane