Re: Parallel scan with SubTransGetTopmostTransaction assert coredump

Maxim Orlov <m.orlov@postgrespro.ru>

From: Maxim Orlov <m.orlov@postgrespro.ru>

To: Greg Nancarrow <gregn4422@gmail.com>

Cc: Pavel Borisov <pashkin.elfe@gmail.com>, Michael Paquier <michael@paquier.xyz>, Pengchengliu <pengchengliu@tju.edu.cn>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>

Date: 2021-06-22T15:06:49Z

Lists: pgsql-hackers

Attachments

v3-0001-PG14-Fix-parallel-worker-failed-assertion-and-coredump.patch (text/x-diff) patch v3-0001

The analysis in the beginning of the discussion seems to be right, but 
the fix v2 looks too invasive for me.

Personally, I'd like not to remove snapshot even if transaction is 
read-only. I propose to consider "xid < TransactionXmin" as a legit case 
and just promote xid to TransactionXmin.

It's annoying this old bug still not fixed. What do you think?
---
Best regards,
Maxim Orlov.

Commits

Fix broken snapshot handling in parallel workers.
- 96f6ef9fe451 10.19 landed
- 198cf81e2c64 11.14 landed
- f4b77e82ebf4 12.9 landed
- bc062cb93823 13.5 landed
- 11c1239881b3 14.0 landed
- a780b2fcce6c 15.0 landed
Doc: move some catalogs.sgml entries to the right place.
- 713a431c781f 14.0 cited
Stamp 13.2.
- 3fb4c75e857a 13.2 cited
Create an infrastructure for parallel computation in PostgreSQL.
- 924bcf4f16d5 9.5.0 cited