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

Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> writes:
> In this build you can see the output of the following at the end,
> which might provide clues to the initiated. You might need to click a
> small triangle to unfold the commands' output.

> cat ./src/test/subscription/tmp_check/log/002_types_publisher.log
> cat ./src/test/subscription/tmp_check/log/002_types_subscriber.log
> cat ./src/test/subscription/tmp_check/log/regress_log_002_types

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.
I think perhaps this reflects a failed attempt to launch a worker,
which the caller does not realize has failed to launch because of the
lack of worker-fork-failure error recovery I bitched about months ago
[1], leading to subscription startup waiting forever for a worker that's
never going to report finishing.

I see Amit K. just posted a patch in that area [2], haven't looked at it
yet.

regards, tom lane

[1] https://www.postgresql.org/message-id/4905.1492813727@sss.pgh.pa.us
[2] https://www.postgresql.org/message-id/CAA4eK1KDfKkvrjxsKJi3WPyceVi3dH1VCkbTJji2fuwKuB=3uw@mail.gmail.com