Re: Corruption during WAL replay

At Mon, 24 Jan 2022 23:33:20 +0300, Daniel Shelepanov <deniel1495(at)mail(dot)ru> wrote in
> Hi. This is my first attempt to review a patch so feel free to tell me
> if I missed something.

Welcome!

> As of today's state of REL_14_STABLE
> (ef9706bbc8ce917a366e4640df8c603c9605817a), the problem is
> reproducible using the script provided by Daniel Wood in this
> (1335373813(dot)287510(dot)1573611814107(at)connect(dot)xfinity(dot)com) message. Also,
> the latest patch seems not to be applicable and requires some minor
> tweaks.

Thanks for the info. The reason for my failure is checksum was
enabled.. After disalbing both fpw and checksum (and wal_log_hints)
allows me to reproduce the issue. And what I found is:

v3 patch:
> vxids = GetVirtualXIDsDelayingChkpt(&nvxids, DELAY_CHKPT_COMPLETE);
!> if (0 && nvxids > 0)
> {

Ugggggggh! It looks like a debugging tweak but it prevents everything
from working.

The attached is the fixed version and it surely works with the repro.

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center