PARALLEL_INSTANCE_GROUP

Property	Description
Parameter type	String
Syntax	PARALLEL_INSTANCE_GROUP = service_name | group_name
Default value	There is no default value; parallel execution is enabled across all currently active instances.
Modifiable	ALTER SESSION, ALTER SYSTEM
Range of values	Any service name or 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 services or 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. If used in conjunction with services, then parallel operations will spawn parallel execution processes only on instances defined in the service. If used in conjunction with INSTANCE_GROUPS, then 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 service or group that does not exist, then the operation runs serially. No parallelism is used.

Note:

1. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter where upper(name) = ‘PARALLEL_INSTANCE_GROUP’;

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE		ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
parallel_instance_group		TRUE	TRUE	IMMEDIATE	TRUE		FALSE	instance group to use for all parallel operations

Oracle initializatoin parameters