ALTER NODE

ALTER NODE — alter a cluster node

Synopsis

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

Description

ALTER NODE is a new SQL command specific to Postgres-XL that modifies cluster node information in catalog pgxc_node.

Node connection that has been modified does not guarantee that connection information cached in the pooler is updated accordingly.

ALTER 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 true.

PREFERRED

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

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

A Datanode can be modified as PRIMARY and as PREFERRED as many times as necessary.

A node type cannot be modified.

Examples

Modify a Coordinator node located on local machine to use port 6543.

ALTER NODE coord_node WITH (PORT = 6543, HOST = 'localhost');

Compatibility

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