After setting up the logical replica, any DDL on the primary is going to break the replication.
You'll see an error like:
2026-08-10 15:28:23.867 UTC [427] ERROR: logical replication target relation "public.t1" is missing replicated column: "a"There's no way to check this error except from the log.
pg_stat_subscription_stats.apply_error_count will increase every 5 seconds as the apply worker spawns and fails. Every 5 seconds seems not configurable.
There is an option to disable subscription on errors:
ALTER SUBSCRIPTION ... SET (disable_on_error = true)With disable_on_error, pg_subscription.subenabled will be set to false if there are any errors.