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:

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