REALIGN_CONTROL_NODES
Causes Vertica to re-evaluate which nodes in the cluster or subcluster are control nodes and which nodes are assigned to them as dependents when large cluster is enabled. Call this function after altering fault groups in an Enterprise Mode database, or changing the number of control nodes in either database mode. After calling this function, query the
V_CATALOG.CLUSTER_LAYOUT system table to see the proposed new layout for nodes in the cluster. You must also take additional steps before the new control node assignments take effect. See Changing the number of control nodes and realigning for details.
Note
In Vertica versions prior to 10.0.1, control node assignments weren't restricted to be within the same Eon Mode subcluster. If you attempt to realign control nodes in a subcluster whose control nodes have dependents in other subclusters, this function returns an error. In this case, you must realign the control nodes in those other subclusters first. Realigning the other subclusters fixes the cross-subcluster dependencies, allowing you to realign the control nodes in the original subcluster you attempted to realign.This is a meta-function. You must call meta-functions in a top-level SELECT statement.
Behavior type
VolatileSyntax
In Enterprise Mode:
REALIGN_CONTROL_NODES()
In Eon Mode:
REALIGN_CONTROL_NODES('subcluster_name')
Parameters
subcluster_name- The name of the subcluster where you want to realign control nodes. Only the nodes in this subcluster are affected. Other subclusters are unaffected. Only allowed when the database is running in Eon Mode.
Privileges
SuperuserExamples
In an Enterprise Mode database, choose control nodes from all nodes and assign the remaining nodes to a control node:
=> SELECT REALIGN_CONTROL_NODES();
In an Eon Mode database, re-evaluate the control node assignments in the subcluster named analytics:
=> SELECT REALIGN_CONTROL_NODES('analytics');