NAME

       CREATE_NODE - create a new cluster node

SYNOPSIS

       CREATE NODE nodename WITH
         (
           [ TYPE = nodetype,]
           [ HOST = hostname,]
           [ PORT = portnum,]
           [ PRIMARY [ = boolean ],]
           [ PREFERRED [ = boolean ] ]
         )

DESCRIPTION

           Note
           The following description applies only to Postgres-XC

       CREATE NODE is new SQL query specific to Postgres-XC since 0.9.7 that creates a new entry
       in catalog table pgxc_node with node data.

       This node data is directly used by a Coordinator session when connecting to build
       connection data to cluster nodes through Postgres-XC pooler.

       Node connection information is created on pooler only if it has not been the case yet on
       Coordinator connected at the moment of connection.

       CREATE NODE only runs on the local node where it is launched.

PARAMETERS

       nodename
           The name of the selected cluster node.

       TYPE
           The type of the cluster node. It is possible to specify a Coordinator node or a
           Datanode node.

       PRIMARY
           Defines if the cluster node is used as a primary node for replicated write operations.
           A boolean value can be specified. In case no value is specified, PRIMARY acts like
           false.

           To avoid deadlock and make update consistetnt, you should specify the same PRIMARY
           node at all the nodes.

       PREFERRED
           Defines if the cluster node is used as a preferred node for replicated read operations
           if no node is determined. A boolean value can be specified. In case no value is
           specified, PREFERRED acts like false.

           You can specify different PREFERRED node at different coordinator. This parameter
           affects performance of your Postgres-XC cluster. If you configure a datanode where you
           configure a coordinator, you should specify PREFERRED for the coordinator to such a
           local datanode. This will save network communication and improve cluster-wide
           performance.

       nodetype
           The node type for given cluster node. Possible values are: 'coordinator' for a
           Coordinator node and 'datanode' for a Datanode node.

       hostname
           The hostname or IP used to connect to the cluster node.

       portnum
           The port number used to connect to the cluster node.

NOTES

       nodename remains constant as long as it is in use.

       When using a cluster with 1 Coordinator and 1 Datanode on each server, Defining the local
       Datanode as PREFERRED can greatly improve the performance of a system by avoiding any
       network overhead for replicated reads, as in this case a local socket is used for
       communication between nodes. This has even more effects when the application uses heavily
       replicated table for remote join operations and that those operations can be operated on
       the local PREFERRED node.

EXAMPLES

       Create a Coordinator node located on local machine using port 6543

           CREATE NODE node2 WITH (TYPE = 'coordinator', HOST = 'localhost', PORT = 6543);

       Create a Datanode which is a preferred and primary node located on remote machine with IP
       '192.168.0.3' on port 8888.

           CREATE NODE node2 WITH (TYPE = 'datanode', HOST = '192.168.0.3', PORT = 8888, PRIMARY, PREFERRED);

COMPATIBILITY

       CREATE NODE does not conform to the SQL standards, it is a Postgres-XC specific command.