Re: Instability in select_parallel regression test

On Sun, Feb 19, 2017 at 5:54 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> However, it looks like there's a race condition here, because the slot
> doesn't get freed up at the same time that the PID gets set to 0.
> That actually happens later, when the postmaster calls
> maybe_start_bgworker() or DetermineSleepTime() and one of those
> functions calls ForgetBackgroundWorker(). We could tighten this up by
> changing CleanupBackgroundWorker() to also call
> ForgetBackgroundWorker() immediately after calling
> ReportBackgroundWorker() if rw->rw_terminate ||
> rw->rw_worker.bgw_restart_time == BGW_NEVER_RESTART. If we do that
> BEFORE sending the notification to the starting process, that closes
> this hole. Almost.

And here's a patch implementing something along those lines.

--
Robert Haas
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