1. Database Reference
  2. Initialization Parameters
  3. Initialization Parameters
  4. QUERY_REWRITE_ENABLED

2.294 QUERY_REWRITE_ENABLED

Use QUERY_REWRITE_ENABLED to enable or disable query rewriting globally for the database.

Property Description

Parameter type

String

Syntax

QUERY_REWRITE_ENABLED = { false | true | force }

Default value

If OPTIMIZER_FEATURES_ENABLE is set to 10.0.0 or higher, then true

If OPTIMIZER_FEATURES_ENABLE is set to 9.2.0 or lower, then false

Modifiable

ALTER SESSION, ALTER SYSTEM

Modifiable in a PDB

Yes

Basic

No

Oracle RAC

Multiple instances can have different values.

Values

  • false

    Oracle does not use rewrite.

  • true

    Oracle costs the query with rewrite and without rewrite and chooses the method with the lower cost.

  • force

    Oracle always uses rewrite and does not evaluate the cost before doing so. Use force when you know that the query will always benefit from rewrite and when reduction in compile time is important.

To take advantage of query rewrite for a particular materialized view, you must enable query rewrite for that materialized view, and you must enable cost-based optimization.

See Also: