PGXC_NODE

PGXC_NODE records information about cluster nodes.

**Table 1** PGXC_NODE columns
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)

        

      

    
   