Looking again, I have two thoughts for making things easier: 1. I don't think wait_for_write_catchup is necessary, because calling wait_for_catchup() and omitting the 'mode' and 'lsn' arguments would already do the same thing. So what we should do is patch places that currently give those two arguments, so that they don't.
2. Because wait_for_replay_catchup is an instance method, passing the second node as argument is needlessly noisy, because that's already known as $self. So we can just say $primary_node->wait_for_replay_catchup($standby_node); -- Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/