Logical replication requires several configuration options to be set.
   On the publisher side, wal_level must be set to
   logical, and max_replication_slots
   must be set to at least the number of subscriptions expected to connect,
   plus some reserve for table synchronization.  And
   max_wal_senders should be set to at least the same as
   max_replication_slots plus the number of physical
   replicas that are connected at the same time.
  
   The subscriber also requires the max_replication_slots
   to be set.  In this case it should be set to at least the number of
   subscriptions that will be added to the subscriber.
   max_logical_replication_workers must be set to at
   least the number of subscriptions, again plus some reserve for the table
   synchronization.  Additionally the max_worker_processes
   may need to be adjusted to accommodate for replication workers, at least
   (max_logical_replication_workers
   + 1).  Note that some extensions and parallel queries
   also take worker slots from max_worker_processes.