Dear Amit,
> Can't we use WaitLatch in the case of SHM_MQ_WOULD_BLOCK as we are
> using it for the same case at some other place in the code? We can use
> the same nap time as we are using in the leader apply worker.
I'm not sure whether such a short nap time is needed or not.
Because unlike leader apply worker, parallel apply workers do not have timeout like wal_receiver_timeout,
so they do not have to check so frequently and send feedback to publisher.
But basically I agree that we can use same logic as leader.
Best Regards,
Hayato Kuroda
FUJITSU LIMITED