Horton

Re: Adding REPACK [concurrently]

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Antonin Houska <ah@cybertec.at>
Cc: Mihail Nikalayeu <mihailnikalayeu@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Andres Freund <andres@anarazel.de>, Srinath Reddy Sadipiralla <srinath2133@gmail.com>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Pg Hackers <pgsql-hackers@lists.postgresql.org>, Robert Treat <rob@xzilla.net>
Date: 2026-05-05T15:02:39Z
Lists: pgsql-hackers 
On 2026-May-05, Antonin Houska wrote:

> However, I failed to notice that COMMIT record of
> a transaction listed in the xl_running_xacts WAL record is not guaranteed to
> follow the xl_running_xacts record in WAL. In other words, even if
> xl_running_xacts is created before a COMMIT record of the contained
> transaction, it may end up at higher LSN in WAL. So the cleanup I relied on
> might not take place.

That's pretty bad news.

> I've got no good idea how to fix that. Not sure I'm able to pursue the
> "database-specific snapshots" feature now.

It appears that the only reasonable course of action at this point is to
revert 0d3dba38c777.

-- 
Álvaro Herrera        Breisgau, Deutschland  —  https://www.EnterpriseDB.com/