Re: pgsql: Add parallel-aware hash joins.

I wrote:
> I ran a couple dozen test cycles on gaur without a failure.  That's
> not enough to really prove anything, but it's more successes than I was
> getting before.  I pushed the patch so we can see what the rest of the
> buildfarm thinks.

The early returns indicate that that problem is fixed; but now that the
noise level is down, it's possible to see that brolga is showing an actual
crash in the PHJ test, perhaps one time in four.  So we're not out of
the woods yet.  It seems to consistently look like this:

2017-12-21 17:34:52.092 EST [2252:4] LOG:  background worker "parallel worker" (PID 3584) was terminated by signal 11
2017-12-21 17:34:52.092 EST [2252:5] DETAIL:  Failed process was running: select count(*) from foo
      left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
      on foo.id < ss.id + 1 and foo.id > ss.id - 1;
2017-12-21 17:34:52.092 EST [2252:6] LOG:  terminating any other active server processes


Also, what the devil is happening on skink?

            regards, tom lane