cluster, clusterAllReplicas

Note

All available clusters are listed in the system.clusters table.

cluster_name – Name of a cluster that is used to build a set of addresses and connection parameters to remote and local servers.

Using the cluster and table functions are less efficient than creating a Distributed table because in this case, the server connection is re-established for every request. When processing a large number of queries, please always create the Distributed table ahead of time, and don’t use the cluster and clusterAllReplicas table functions.

• Accessing a specific cluster for data comparison, debugging, and testing.
• Infrequent distributed requests that are made manually.

Connection settings like host, port, user, password, compression, are taken from <remote_servers> config section. See details in Distributed engine.

See Also