PARALLEL_INSTANCE_GROUP

Property	Description
Parameter type	String
Syntax	`PARALLEL_INSTANCE_GROUP =` `group_name`
Default value	A group consisting of all instances currently active
Modifiable	`ALTER SESSION`, `ALTER SYSTEM`
Range of values	Any group name specified in the `INSTANCE_GROUPS` parameter of any active instance
Real Application Clusters	Multiple instances can have different values.

PARALLEL_INSTANCE_GROUP is a Real Application Clusters parameter that you can specify in parallel mode only. Used in conjunction with the INSTANCE_GROUPS parameter, it lets you restrict parallel query operations to a limited number of instances.

This parameter identifies the parallel instance group Oracle will use for spawning parallel execution processes. Parallel operations will spawn parallel execution processes only on instances that specify a matching group in their INSTANCE_GROUPS parameter.

If the value assigned to PARALLEL_INSTANCE_GROUP is the name of a group that does not exist, then the operation runs serially. No parallelism is used.