SHOW POOL_NODES displays the node id, the hostname, the port, the status, the weight (only meaningful if you use the load balancing mode), the role, the SELECT query counts issued to each backend, whether each node is the load balance node or not, the replication delay (only if in streaming replication mode) and last status change time. In addition to this replication state and sync state are shown for standby nodes in Pgpool-II 4.1 or after. Also actual node status and node role are shown in Pgpool-II 4.3 or after.
The possible values in the status column are explained in the pcp_node_info reference.
If the hostname is something like "/tmp", that means Pgpool-II is connecting to backend by using UNIX domain sockets. The SELECT count does not include internal queries used by Pgpool-II. Also the counters are reset to zero upon starting up of Pgpool-II. The last status change time is initially set to the time Pgpool-II starts. After that whenever "status" or "role" is changed, it is updated.
Here is an example session:
test=# show pool_nodes; node_id | hostname | port | status | pg_status | lb_weight | role | pg_role | select_cnt | load_balance_node | replication_delay | replication_state | replication_sync_state | last_status_change ---------+----------+-------+--------+-----------+-----------+---------+---------+------------+-------------------+-------------------+-------------------+------------------------+--------------------- 0 | /tmp | 11002 | up | up | 0.500000 | primary | primary | 0 | false | 0 | | | 2021-02-27 15:10:19 1 | /tmp | 11003 | up | up | 0.500000 | standby | standby | 0 | true | 0 | streaming | async | 2021-02-27 15:10:19 (2 rows)