REBALANCE_CLUSTER

Rebalances the database cluster synchronously as a session foreground task.

Rebalances the database cluster synchronously as a session foreground task. REBALANCE_CLUSTER returns only after the rebalance operation is complete. If the current session ends, the operation immediately aborts. To rebalance the cluster as a background task, call START_REBALANCE_CLUSTER.

On large cluster arrangements, you typically call REBALANCE_CLUSTER in a flow (see Changing the number of control nodes and realigning). After you change the number and distribution of control nodes (spread hosts), run REBALANCE_CLUSTER to achieve fault tolerance.

For detailed information about rebalancing tasks, see Rebalancing data across nodes.

Tip

By default, before performing a rebalance, Vertica queries system tables to compute the size of all projections involved in the rebalance task. This query can add significant overhead to the rebalance operation. To disable this query, set projection configuration parameter RebalanceQueryStorageContainers to 0.

This is a meta-function. You must call meta-functions in a top-level SELECT statement.

Behavior type

Volatile

Syntax

REBALANCE_CLUSTER()

Privileges

Superuser

Examples

=> SELECT REBALANCE_CLUSTER();
REBALANCE_CLUSTER
-------------------
 REBALANCED
(1 row)