Re: BUG #19102: Assertion failure in generate_orderedappend_paths with aggregate pushdown

Kuntal Ghosh <kuntalghosh.2007@gmail.com>

From: Kuntal Ghosh <kuntalghosh.2007@gmail.com>

To: kuntalghosh.2007@gmail.com, pgsql-bugs@lists.postgresql.org

Cc: akorotkov@postgresql.org

Date: 2025-11-03T05:57:51Z

Lists: pgsql-bugs

Commits

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Fix assertion failure in generate_orderedappend_paths()
- 500f646368e4 18.1 landed
- c1777f2d6d43 19 (unreleased) landed
Avoid creating duplicate ordered append paths
- 0ea5eee37606 19 (unreleased) landed

Attachments

0001-Remove-incorrect-assertion-for-childrel-rows-in-orde.patch (application/octet-stream) patch 0001

On Mon, Nov 3, 2025 at 11:22 AM PG Bug reporting form <
noreply@postgresql.org> wrote:

>
> Server crashes with assertion failure:
> TRAP: FailedAssertion("childrel->rows > 0", File: "allpaths.c", Line: 1983)
>
> To fix the issue, we can replace the direct division with
> clamp_row_est(childrel->rows) to safely handle zero, and remove the
> incorrect assertion:
>
> -   Assert(childrel->rows > 0);
> -   path_fraction /= childrel->rows;
> +   path_fraction /= clamp_row_est(childrel->rows);
>
> Added a patch with the proposed fix and regression test.

-- 
Thanks & Regards,
Kuntal Ghosh