Re: Design for In-Core Logical Replication

I think it's important for communication channels to be defined separately from the subscriptions.

So, I'd rather have:

CREATE CONNECTION machine1;
CREATE CONNECTION machine2;

CREATE SUBSCRIPTION TO PUBLICATION mypub;

I'm not certain the subscription needs to be named. IMO, a publication should have the same properties on all nodes (so any node may become the primary source). If a subscriber needs different behaviour for a publication, it should be created as a different publication.

Documenting that ThisPub is different from ThatPub is easier than documenting that ThisPub on node 1/2/4 is different from ThisPub on node 7/8, except Node 7 is temporarily on Node 4 too (database X instead of database Y) due to that power problem.

Clearly this is advanced. An initial implementation may only allow mypub from a single connection.

I also suspect multiple publications will be normal even if only 2 nodes. Old slow moving data almost always got different treatment than fast-moving data; even if only defining which set needs to hit the other node first and which set can trickle through later.