Re: src/test/subscription/t/002_types.pl hanging on particular environment

I wrote:
> The subscriber log includes
> 2017-09-18 08:43:08.240 UTC [15672] WARNING:  out of background worker slots
> 2017-09-18 08:43:08.240 UTC [15672] HINT:  You might need to increase max_worker_processes.

> Maybe that's harmless, but I'm suspicious that it's a smoking gun.

Actually: looking at the place where this is issued, namely
logicalrep_worker_launch, and comparing it to the cleanup logic
in WaitForReplicationWorkerAttach, it looks to me like the problem
is we're failing to do logicalrep_worker_cleanup() in this case.
We have initialized a logical rep worker slot, and we're just
walking away from it.

I'll go see if I can't reproduce this by injecting random failures right
there.

			regards, tom lane