The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/10/sql-altersubscription.html
Description:
If the logical replication subscription is owned by a role that is not
allowed to login (for example, if the LOGIN privilege is removed after the
subscription is created) then the logical replication worker (which uses the
owner to connect to the database) will start to fail with this error
(repeated every 5 seconds), which is pretty much undocumented:
FATAL: role "XXX" is not permitted to log in
LOG: background worker "logical replication worker" (PID X) exited with
exit code 1
You might want to include that error message in the docs, to ensure that web
searches for it bring the user to this documentation.