|Real Application Clusters||Multiple instances can have different values.|
QUERY_REWRITE_INTEGRITY determines the degree to which Oracle must enforce query rewriting. At the safest level, Oracle does not use query rewrite transformations that rely on unenforced relationships.
Oracle enforces and guarantees consistency and integrity.
Oracle allows rewrites using relationships that have been declared, but that are not enforced by Oracle.
Oracle allows rewrites using unenforced relationships. Materialized views are eligible for rewrite even if they are known to be inconsistent with the underlying detail data.