INSTANCE_GROUPS

Property	Description
Parameter type	String
Syntax	INSTANCE_GROUPS = group_name [, group_name ] ...
Default value	There is no default value.
Modifiable	No
Range of values	One or more instance group names, separated by commas
Basic	No
Real Application Clusters	Multiple instances can have different values.

Note:

1. The INSTANCE_GROUPS parameter is deprecated. It is retained for backward compatibility only.

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

This parameter specifies one or more instance groups and assigns the current instance to those groups. If one of the specified groups is also specified in the PARALLEL_INSTANCE_GROUP parameter, then Oracle allocates query processes for a parallel operation from this instance.

2. Related parameter: PARALLEL_INSTANCE_GROUP

   INSTANCE_GROUPS is a Parallel Server parameter. 

3. 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) = ‘INSTANCE_GROUPS’;

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
instance_groups		TRUE	FALSE	FALSE	FALSE	FALSE	list of instance group names

Oracle initializatoin parameters