Re: WaitLatchOrSocket seems to not count to 4 right...

On Tue, Feb 8, 2022 at 1:48 PM Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com> wrote:
> On 2022/02/08 7:00, Greg Stark wrote:
> > Unless I'm misreading this code I think the nevents in
> > WaitLatchOrSocket should really be 4 not 3. At least there are 4 calls
> > to AddWaitEventToSet in it and I think it's possible to trigger all 4.
>
> Good catch! I think you're right.
>
> As the quick test, I confirmed that the assertion failure happened when I passed four possible events to WaitLatchOrSocket() in postgres_fdw.
>
> TRAP: FailedAssertion("set->nevents < set->nevents_space", File: "latch.c", Line: 868, PID: 54424)

Yeah, the assertion shows there's no problem, but we should change it
to 4 (and one day we should make it dynamic and change udata to hold
an index instead of a pointer...) or, since it's a bit silly to add
both of those events, maybe we should do:

- if ((wakeEvents & WL_POSTMASTER_DEATH) && IsUnderPostmaster)
- AddWaitEventToSet(set, WL_POSTMASTER_DEATH, PGINVALID_SOCKET,
- NULL, NULL);
-
if ((wakeEvents & WL_EXIT_ON_PM_DEATH) && IsUnderPostmaster)
AddWaitEventToSet(set, WL_EXIT_ON_PM_DEATH, PGINVALID_SOCKET,
NULL, NULL);
+ else if ((wakeEvents & WL_POSTMASTER_DEATH) && IsUnderPostmaster)
+ AddWaitEventToSet(set, WL_POSTMASTER_DEATH, PGINVALID_SOCKET,
+