STANDBY STATUS node for PostgreSQL

SELECT pid,
      usesysid,
      usename,
      application_name,
      client_addr::text,
      client_hostname::text,
      client_port,
      backend_start,
      backend_xmin,
      state,
      sent_lsn::text,
      write_lsn::text,
      flush_lsn::text,
      replay_lsn::text,
      write_lag::text,
      flush_lag::text,
      replay_lag::text,
      sync_priority,
      sync_state,
      reply_time,
      pg_current_wal_lsn()::text "current_wal_lsn"
 FROM pg_stat_replication