SET_SCALING_FACTOR

Sets the scaling factor that determines the number of storage containers used when rebalancing the database and when using local data segmentation is enabled. See Cluster Scaling for details.

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

Behavior type

Syntax

SET_SCALING_FACTOR( factor )

Parameters

factor

An integer value between 1 and 32. Vertica uses this value to calculate the number of storage containers each projection is broken into when rebalancing or when local data segmentation is enabled.

Privileges

Superuser

Best practices

The scaling factor determines the number of storage containers that Vertica uses to store each projection across the database during rebalancing when local segmentation is enabled. When setting the scaling factor, follow these guidelines:

• The number of storage containers should be greater than or equal to the number of partitions multiplied by the number of local segments:

  num-storage-containers >= ( num-partitions * num-local-segments )

• Set the scaling factor high enough so rebalance can transfer local segments to satisfy the skew threshold, but small enough so the number of storage containers does not result in too many ROS containers, and cause ROS pushback. The maximum number of ROS containers (by default 1024) is set by configuration parameter ContainersPerProjectionLimit.

Examples

=> SELECT SET_SCALING_FACTOR(12);
 SET_SCALING_FACTOR
--------------------
 SET
(1 row)