Re: Refactor recovery conflict signaling a little

On Mon, Mar 9, 2026 at 11:28 PM Heikki Linnakangas <hlinnaka(at)iki(dot)fi> wrote:
>
> On 09/03/2026 17:02, Xuneng Zhou wrote:
> > Did you use Alexander’s reproducer script? I tried reproducing with a
> > 1 ms pg_usleep() added to all three functions that clear
> > MyProc->pendingRecoveryConflicts, but I still couldn’t reproduce the
> > issue.
>
> I used the attached, to be precise. With that it fails every time for
> me. I'm not sure if the "if (am_walsender)" check is necessary, I added
> it just to make the test run faster.
>
> - Heikki

I was able to reproduce the issue using a wider sleep window as you
suggested and can confirm that the flag is not cleared after applying
the patch. Below are two logs—one from a successful run and one from a
failed run. I'll look further into the patch later on.

failed run:
startup[1418915] LOG: DBG SignalRecoveryConflict target_pid=1419118
reason=4 old_mask=0x0 new_mask=0x10
walsender[1419118] LOG: DBG ProcArrayEndTransaction(no-xid) CLEARING
pendingRecoveryConflicts=0x10

successful run:
startup[1433218] LOG: DBG SignalRecoveryConflict target_pid=1433406
reason=4 old_mask=0x0 new_mask=0x10
walsender[1433406] LOG: DBG ProcessInterrupts handler fired 1
time(s), pending=0x10 -- processing
walsender[1433406] ERROR: canceling statement due to conflict with recovery

--
Best,
Xuneng