Re: Failing assertion while taking a restartpoint during crash recovery

On Tue, Aug 18, 2026 at 1:37 PM Imran Zaheer <imran(dot)zhir(at)gmail(dot)com> wrote:
> I was looking into the patch

Thanks!

> * Instead of setting the shared state in StartupXLOG, why not set it
> in the StartupSUBTRANS itself?

*If* we take this approach, I think the flag should no longer mean that hot
standby initialization has started pg_subtrans, but rather that
StartupSUBTRANS() has completed. We would therefore also need to rename
the flag and update the comments accordingly.

For a bug fix in stable branches, I would prefer to keep the change as
small as possible. Also, subtrans.c says that there are no XLOG
interactions, so having it update shared recovery state in
xlogrecovery.c feels a bit odd to me. I therefore prefer the current
patch and approach.

> * Other than that we also call TruncateSUBTRANS() while creating a
> checkpoint; maybe we can also improve the guard here, although the
> assertion under TruncateSUBTRANS could be enough?
>
> @@ -7879,7 +7878,7 @@ CreateCheckPoint(int flags)
> * in subtrans.c). During recovery, though, we mustn't do this because
> * StartupSUBTRANS hasn't been called yet.
> */
> - if (!RecoveryInProgress())
> + if (!RecoveryInProgress() && RecoverySubtransInitialized())
> TruncateSUBTRANS(GetOldestTransactionIdConsideredRunning());

I don't think this extra check is necessary. If !RecoveryInProgress(),
StartupSUBTRANS() should already have been called, so the existing
guard should be sufficient.

Regards,

--
Fujii Masao