Re: Unportable implementation of background worker start

On 2017-04-26 11:42:38 -0400, Tom Lane wrote:
> 1. Let HEAD stand as it is. We have a problem with slow response to
> bgworker start requests that arrive while ServerLoop is active, but that's
> a pretty tight window usually (although I believe I've seen it hit at
> least once in testing).
>
> 2. Reinstall the pselect patch, blacklisting NetBSD and HPUX and whatever
> else we find to be flaky. Then only the blacklisted platforms have the
> problem.

That seems unattractive at this point. I'm not looking forward to
having to debug more random platforms that implement this badly in a
yet another weird way.

> 3. Go ahead with converting the postmaster to use WaitEventSet, a la
> the draft patch I posted earlier. I'd be happy to do this if we were
> at the start of a devel cycle, but right now seems a bit late --- not
> to mention that we really need to fix 9.6 as well.

Yea, backpatching this to 9.6 seems like a bigger hammer than
appropriate. I'm on the fence WRT master, I think there's an argument
to be made that this is going to become a bigger and bigger problem, and
that we'll wish in a year or two that we had fewer releases with
parallelism etc that don't use WaitEventSets.

> I'm leaning to doing #1 plus the maybe_start_bgworker change. There's
> certainly room for difference of opinion here, though. Thoughts?

I see you did the bgworker thing - that seems good to me.

Thanks,

Andres