OPTIMIZER_INDEX_COST_ADJ

Property	Description
Parameter type	Integer
Default value	100
Modifiable	ALTER SESSION, ALTER SYSTEM
Range of values	1 to 10000

OPTIMIZER_INDEX_COST_ADJ lets you tune optimizer behavior for access path selection to be more or less index friendly—that is, to make the optimizer more or less prone to selecting an index access path over a full table scan.

The default for this parameter is 100 percent, at which the optimizer evaluates index access paths at the regular cost. Any other value makes the optimizer evaluate the access path at that percentage of the regular cost. For example, a setting of 50 makes the index access path look half as expensive as normal.

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) = ‘OPTIMIZER_INDEX_COST_ADJ’;

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
optimizer_index_cost_adj	100	TRUE	TRUE	IMMEDIATE	TRUE	FALSE	optimizer index cost adjustment

Oracle initializatoin parameters