Re: Bug in amcheck?

Mikhail Nikalayeu <mihailnikalayeu@gmail.com>

From: Mihail Nikalayeu <mihailnikalayeu@gmail.com>

To: Konstantin Knizhnik <knizhnik@garret.ru>, akorotkov@postgresql.org, aekorotkov@gmail.com

Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2025-11-18T22:19:00Z

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 amcheck's handling of half-dead B-tree pages
- fbb4b607832d 14.21 landed
- 7792bdc45860 15.16 landed
- 1829016268c3 16.12 landed
- e8ae594458a3 17.8 landed
- 19e786727c4f 18.2 landed
- cbe04e5d729f 19 (unreleased) landed
Fix amcheck's handling of incomplete root splits in B-tree
- a4cb21ea9cd7 14.21 landed
- 721b58fbec5f 15.16 landed
- f2a6df9fd56d 16.12 landed
- 5a2d1df00718 17.8 landed
- 50c63ebb05fc 18.2 landed
- 6c05ef5729c0 19 (unreleased) landed
Add a test for half-dead pages in B-tree indexes
- c085aab27819 19 (unreleased) landed
Add a test for incomplete splits in B-tree indexes
- 1e4e5783e7d7 19 (unreleased) landed
Improve checking of child pages in contrib/amcheck.
- d114cc538715 13.0 cited

Hello!

> Originally I investigated the customer's problem with PG16. And have
> reproduced it for pg16,. I checked that relevant amcheck code was not
> changed since pg16, so I thought that the problem takes place for all
> Postgres versions. But looks like it is not true.

I think it is still broken, but with less probability.
Have you tried injection points on v16? Such a test case will make
things much more clear.

Also, I added Alexander to CC (he is author of bt_child_highkey_check)
- maybe the issue is easily understandable for him.

Best regards,
Mikhail.