Boolean 

Dynamic. Scope = ALTER SYSTEM, ALTER SESSION. 

FALSE 

TRUE | FALSE 

Multiple instances can have different values. 

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

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

• Oracle8i Data Warehousing Guide for information on query rewrite of materialized views.

• Oracle8i Designing and Tuning for Performance and "OPTIMIZER_MODE" for information on cost-based optimization.