Re: BUG #19649: Qual pushdown into GROUP BY subqueries ignores non-equivalence-preserving references to grouping col

пт, 4 сент. 2026 г. в 20:12, Andrei Lepikhov <lepihov(at)gmail(dot)com>:

> On 03/09/2026 23:17, Andrey Rachitskiy wrote:
> > This blocks wrapper-based finer equivalence at pushdown boundaries while
> > preserving existing behavior for truly direct operands.
> I don't like this fix. It causes regressions where we haven't had it
> before.
> Let's see:
>
> CREATE TABLE r(i int, s text, ts timestamptz);
> EXPLAIN (COSTS OFF)
> SELECT * FROM (SELECT i, count(*) c FROM r GROUP BY i) s WHERE i::text =
> '5';
>
> Before:
>
> GroupAggregate
> Group Key: r.i
> -> Sort
> Sort Key: r.i
> -> Seq Scan on r
> Filter: ((i)::text = '5'::text)
>
> With your fix:
>
> HashAggregate
> Group Key: r.i
> Filter: ((r.i)::text = '5'::text)
> -> Seq Scan on r
>
> I think, filter should be pushed down to the scan.
>
> --
> regards, Andrei Lepikhov,
> pgEdge
>

Dear Andrei,

Thanks for the review.

v2 with a correction in the attachment.
I also removed the duplicate logic.

--
Regards,
Rachitskiy Andrey