1.285 QUERY_REWRITE_INTEGRITY
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.
Property | Description |
---|---|
Parameter type |
String |
Syntax |
|
Default value |
|
Modifiable |
|
Modifiable in a PDB |
Yes |
Basic |
No |
Oracle RAC |
Multiple instances can have different values. |
QUERY_REWRITE_INTEGRITY
is relevant for materialized views as well as for foreign key constraints in NOVALIDATE
state.
Values
-
enforced
Oracle enforces and guarantees consistency and integrity.
-
trusted
Oracle allows rewrites using relationships that have been declared, but that are not enforced by Oracle.
-
stale_tolerated
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. You must set the
QUERY_REWRITE_INTEGRITY
initialization parameter tostale_tolerated
before querying an external table in the In-Memory Column Store (IM column store).
If a foreign key constraint is in NOVALIDATE
state, join elimination is not done when QUERY_REWRITE_INTEGRITY=enforced
. This means that queries with joins over a foreign key constraint that is in RELY NOVALIDATE
state can potentially take longer to parse and execute as the optimizer does not trust the RELY
.
See Also:
-
Oracle Database Data Warehousing Guide for more information about query rewrite for materialized views
-
Oracle Database Data Warehousing Guide for more information about the
QUERY_REWRITE_INTEGRITY
parameter