alter_data_node.md

api_name	alter_data_node()
excerpt	Change the configuration of a data node
topics	distributed hypertables multi-node
keywords	multi-node
tags	data nodes distributed hypertables cluster
api	license type community function
seo	robots noindex

import MultiNodeDeprecation from "versionContent/_partials/_multi-node-deprecation.mdx";

alter_data_node() Community

Change the configuration of a data node that was originally set up with add_data_node on the access node.

Only users with certain privileges can alter data nodes. When you alter the connection details for a data node, make sure that the altered configuration is reachable and can be authenticated by the access node.

Required arguments

Name	Description
node_name	Name for the data node

Optional arguments

Name	Description
host	Host name for the remote data node
database	Database name where remote hypertables are created. The default is the database name that was provided in add_data_node
port	Port to use on the remote data node. The default is the $PG port that was provided in add_data_node
available	Configure availability of the remote data node. The default is true meaning that the data node is available for read/write queries

Returns

Column	Description
node_name	Local name to use for the data node
host	Host name for the remote data node
port	Port for the remote data node
database	Database name used on the remote data node
available	Availability of the remote data node for read/write queries

Errors

An error is given if:

• A remote data node with the provided node_name argument does not exist.

Privileges

To alter a data node, you must have the correct permissions, or be the owner of the remote server. Additionally, you must have the USAGE privilege on the timescaledb_fdw foreign data wrapper.

Sample usage

To change the port number and host information for an existing data node dn1:

SELECT alter_data_node('dn1', host => 'dn1.example.com', port => 6999);

Data nodes are available for read/write queries by default. If the data node becomes unavailable for some reason, the read/write query gives an error. This API provides an optional argument, available, to mark an existing data node as available or unavailable for read/write queries. By marking a data node as unavailable you can allow read/write queries to proceed in the cluster. For more information, see the multi-node HA section