Re: VM corruption on standby

> On 10 Sep 2025, at 15:25, Alexander Korotkov <aekorotkov(at)gmail(dot)com> wrote:
>
> I think the approach #2 is more appropriate for bc22dc0e0d, because in
> the critical section we only wait for other processes also in the
> critical section (so, there is no risk they will exit immediately
> after postmaster death making us stuck). I've implemented a patch,
> where waiting on conditional variable is replaced with LWLock-style
> waiting on semaphore. However, custom waiting code just for
> AdvanceXLInsertBuffer() doesn't look good.

Well, at least I'd like to see corruption-free solution for injection point wait too.

> I believe we need some
> general solution. We might have a special kind of condition variable,
> a critical section condition variable, where both waiting and
> signaling must be invoked only in a critical section. However, I dig
> into our Latch and WaitEventSet, it seems there are too many
> assumptions about postmaster death. So, a critical section condition
> variable probably should be implemented on top of semaphore. Any
> thoughts?

We want Latch\WaitEventSet, but for critical section. Is it easier to implement from scratch (from semaphores), or is it easier to fix and maintain existing Latch\WaitEventSet?

Best regards, Andrey Borodin.