PGXC_NODE¶
PGXC_NODE records information about cluster nodes.
Name | Type | Description |
|---|---|---|
node_name | name | Node name |
node_type | "char" | Node type C: CN D: DN |
node_port | integer | Port ID of the node |
node_host | name | Host name or IP address of a node. (If a virtual IP address is configured, its value is a virtual IP address.) |
node_port1 | integer | Port number of a replication node |
node_host1 | name | Host name or IP address of a replication node. (If a virtual IP address is configured, its value is a virtual IP address.) |
hostis_primary | boolean | Whether a switchover occurs between the primary and the standby server on the current node |
nodeis_primary | boolean | Whether the current node is preferred to execute non-query operations in the replication table |
nodeis_preferred | boolean | Whether the current node is preferred to execute queries in the replication table |
node_id | integer | Node identifier |
sctp_port | integer | Specifies the port used by the TCP proxy communication library or SCTP communication library of the primary node to listen to the data channel. |
control_port | integer | Specifies the port used by the TCP proxy communication library or SCTP communication library of the primary node to listen to the control channel. |
sctp_port1 | integer | Specifies the port used by the TCP proxy communication library or SCTP communication library of the standby node to listen to the data channel. |
control_port1 | integer | Specifies the port used by the TCP proxy communication library or SCTP communication library of the standby node to listen to the control channel. |
nodeis_central | boolean | Indicates that the current node is the central node. |
Example¶
Query the number of DNs on a node:
SELECT count(node_name),node_host FROM pgxc_node WHERE node_type='D' GROUP BY 2;
count | node_host
-------+---------------
1 | 192.**.**.10
1 | 192.**.**.11
1 | 192.**.**.12
(3 rows)
Query the CN and DN information of the cluster:
SELECT * FROM pgxc_node;
node_name | node_type | node_port | node_host | node_port1 | node_host1 | hostis_primary | nodeis_primary | nodeis_preferred
| node_id | sctp_port | control_port | sctp_port1 | control_port1 | nodeis_central
--------------+-----------+-----------+----------------+------------+----------------+----------------+----------------+-----------------
-+-------------+-----------+--------------+------------+---------------+----------------
dn_6001_6002 | D | 40000 | 192.**.***.**1 | 45000 | 192.**.**.**2 | t | f | f
| 1644780306 | 40002 | 40003 | 45002 | 45003 | f
dn_6003_6004 | D | 40000 | 192.**.**.**2 | 45000 | 192.**.**.**3 | t | f | f
| -966646068 | 40002 | 40003 | 45002 | 45003 | f
dn_6005_6006 | D | 40000 | 192.**.**.**3 | 45000 | 192.**.***.**1 | t | f | f
| 868850011 | 40002 | 40003 | 45002 | 45003 | f
cn_5001 | C | 8000 | 192.**.***.**1 | 8000 | 192.**.***.**1 | t | f | f
| 1120683504 | 8002 | 8003 | 0 | 0 | f
cn_5002 | C | 8000 | 192.**.**.**2 | 8000 | 192.**.**.**2 | t | f | f
| -1736975100 | 8002 | 8003 | 0 | 0 | f
cn_5003 | C | 8000 | localhost | 8000 | localhost | t | f | f
| -125853378 | 8002 | 8003 | 0 | 0 | t
(6 rows)