Replication causing publisher node to use excessive cpu over time

I’ve got two Postgres 10/Debian stretch systems and have added a publish/subscribe on a single table that isn’t updated very often. The subscriber node is doing very little else.

After a few days, it’s noticeable that the Postgres on the publisher node is constantly using a lot of cpu (26% today) and having a big impact on the system performance even when doing very little. Logging on to the subscriber and removing the subscription sees this value drop to an expect small value.

I can’t see that this can be anything but a bug, but happy for any thoughts :)

Martin Moore