ALTER NODE modifies the definition of an existing node.
ALTER NODE is the internal interface of cluster management tool. You are not advised to use this interface, because doing so affects the cluster.
ALTER NODE nodename WITH ( [ TYPE = nodetype,] [ HOST = hostname,] [ PORT = portnum,] [ HOST1 = 'hostname',] [ PORT1 = portnum,] [ HOSTPRIMARY [ = boolean ],] [ PRIMARY [ = boolean ],] [ PREFERRED [ = boolean ],] [ SCTP_PORT = portnum,] [ CONTROL_PORT = portnum,] [ SCTP_PORT1 = portnum,] [ CONTROL_PORT1 = portnum, ] [ NODEIS_CENTRAL [ = boolean ]] );
The port whose number is specified by PORT is used for internal communications between nodes. Unlike the port number which connect node by external client, it can be queried in the pgxc_node table.
See Parameter description in CREATE NODE.