Re: condition variables

On Thu, Aug 11, 2016 at 2:47 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> Another approach to the problem is to use a latch wait loop. That
> almost works. Interrupts can be serviced, and you can recheck shared
> memory to see whether the condition for proceeding is satisfied after
> each iteration of the loop. There's only one problem: when you do
> something that might cause the condition to be satisfied for other
> waiting backends, you need to set their latch - but you don't have an
> easy way to know exactly which processes are waiting, so how do you
> call SetLatch? I originally thought of adding a function like
> SetAllLatches(ParallelContext *) and maybe that can work, but then I
> had what I think is a better idea, which is to introduce a notion of
> condition variables.

I don't see a CF entry for this. Are you planning to work on this
again soon, Robert?

I have an eye on this patch due to my work on parallel CREATE INDEX.
It would be nice to have some rough idea of when you intend to commit
this.

--
Peter Geoghegan