Re: Leader backend hang on IPC/ParallelFinish when LWLock held at parallel query start

On Fri, Nov 08, 2024 at 11:46:36AM -0500, Tom Lane wrote:
> Noah Misch <noah@leadboat.com> writes:
> > On Thu, Nov 07, 2024 at 02:29:19PM -0500, Tom Lane wrote:
> >> Ah, that could be a way out.  Stick an INTERRUPTS_CAN_BE_PROCESSED()
> >> call somewhere in there?
> 
> > Exactly.  If !INTERRUPTS_CAN_BE_PROCESSED(), proceed as though no workers can
> > be launched.
> 
> >> That could even allow us to revert the
> >> planner change, which would simplify testing of the executor change.
> 
> > True.
> 
> Here's a proposed patch along that line.  I left the test case from
> ac04aa84a alone, since it works perfectly well to test this way too.
> 
> We could argue about whether or not to revert the planner change.
> But I'd prefer to do so, because as things stand it creates a
> hard-to-reason-about source of plan instability.

Looks perfect.  Thank you.