Promoting an asynchronous standby server to synchronous mode is actually a fairly simple procedure. We begin by modifying the primary_conninfo setting in the standby's recovery.conf file to include the application_name value. PostgreSQL differentiates replicas by their stated application name, so if we change this, we can specifically target that particular replica. Any other synchronous standby nodes should be assigned different names.
Once we restart the PostgreSQL server on the streaming standby, it will reconnect to the primary server with the new application_name that we assigned. From this point onward, we can refer to the standby server as node2. Thus, when we alter the synchronous_standby_names variable in the primary ...
