Re: Helper functions for wait_for_catchup() in Cluster.pm

On 2023-Jan-26, Drouvot, Bertrand wrote:

> On 1/24/23 7:27 PM, Alvaro Herrera wrote:

> > 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.
>
> Agree but there is one place where the node passed as the second argument is not the "$self":
>
> src/bin/pg_rewind/t/007_standby_source.pl:$node_b->wait_for_write_catchup('node_c', $node_a);
>
> So it looks like there is still a need for wait_for_write_catchup().

Hmm, I think that one can use the more general wait_for_catchup.

> > 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);
>
> Yeah, but same here, there is places where the node passed as the second argument is not the "$self":
>
> src/bin/pg_rewind/t/007_standby_source.pl:$node_b->wait_for_replay_catchup('node_c', $node_a);
> src/test/recovery/t/001_stream_rep.pl:$node_standby_1->wait_for_replay_catchup($node_standby_2, $node_primary);
> src/test/recovery/t/001_stream_rep.pl:$node_standby_1->wait_for_replay_catchup($node_standby_2, $node_primary);
> src/test/recovery/t/001_stream_rep.pl: $node_standby_1->wait_for_replay_catchup($node_standby_2, $node_primary);
>
> So it looks like there is still a need for wait_for_replay_catchup() with 2 parameters.

Ah, cascading replication. In that case, let's make the second
parameter optional. If it's not given, $self is used.

--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
"En las profundidades de nuestro inconsciente hay una obsesiva necesidad
de un universo lógico y coherente. Pero el universo real se halla siempre
un paso más allá de la lógica" (Irulan)