Parallel_instance_group

[domregchief]

Type:String
Syntax:PARALLEL_INSTANCE_GROUP = group_name
Default:A group consisting of all instances currently active
Modify:ALTER SESSION, ALTER SYSTEM
Range:Any group name specified in the INSTANCE_GROUPS parameter of any
active instance
Rac:Multiple instances can have different values.
Notes: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.