> On Mar 25, 2025, at 20:56, Phillip Diffley <phillip6...@gmail.com> wrote:
>
> Is there a message type that is used to confirm what logs have been
> successfully consumed?
You're looking for Standby Status Update:
https://www.postgresql.org/docs/current/protocol-replication.html#PROTOCOL-REPLICATION-STANDBY-STATUS-UPDATE
The logical replication protocol is a superset of the binary replication
protocol, so many of the same messages are used.
> The part I am uncertain about is what "after" means here, since LSNs are not
> presented in order, and the order of data streamed over the replication slot
> does not match the order of the data in the WAL.
I think there's a misunderstanding here (possibly my fault). Transactions are
always presented to the output plugin in commit order, and LSNs can be reliably
used to determine the time ordering of commits. LSNs are exactly what is used
to determine how far into the WAL the replication slot has gotten.
