trusty (7) CREATE_NODE.7.gz

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.