pcp_promote_node promotes the given node as new master to Pgpool-II. In master/slave streaming replication only. Please note that this command does not actually promote standby PostgreSQL backend: it just changes the internal status of Pgpool-II and trigger failover and users have to promote standby PostgreSQL outside Pgpool-II.
The index of backend node to promote as new master.
Wait until all clients are disconnected (unless client_idle_limit_in_recovery is -1 or recovery_timeout is expired).