Speeding up enable of constraints

Question

I have various constraints that used to take seconds and now are taking up to half an hr to enable. The data in the tables is static, it has increased or decreased. Does anyone know how to speed up the enabling of constraints on a table? What goes on behind the scenes after issuing alter table <table_name> enable constraint <constraint_name>;
Thankis

Answer 1

Dear HouseofHunger,
Please tell me if that online documentation is enough for you or not?
http://download.oracle.com/docs/cd/E11882_01/server.112/e17118/statements_3001.htm#i2183600
+"+
+Restrictions on Modifying Constraints Modifying constraints is subject to the following restrictions:+
+*You cannot change the state of a NOT DEFERRABLE constraint to INITIALLY DEFERRED.+
+*If you specify this clause for an index-organized table, then you cannot specify any other clauses in the same statement.+
+*You cannot change the NOT NULL constraint on a foreign key column of a reference-partitioned table, and you cannot change the state of a partitioning referential constraint of a reference-partitioned table.+
+See Also:+
+"*Changing the State of a Constraint: Examples*"+
+"+
+"+
+Changing the State of a Constraint: Examples The following statement places in ENABLE VALIDATE state an integrity constraint named emp_manager_fk in the employees table:+
+ALTER TABLE employees+
+ENABLE VALIDATE CONSTRAINT emp_manager_fk+
+EXCEPTIONS INTO exceptions;+
+Each row of the employees table must satisfy the constraint for Oracle Database to enable the constraint. If any row violates the constraint, then the constraint remains disabled. The database lists any exceptions in the table exceptions. You can also identify the exceptions in the employees table with the following statement:+
+SELECT e.*+
+FROM employees e, exceptions ex+
+WHERE e.rowid = ex.row_id+
+AND ex.table_name = 'EMPLOYEES'+
+AND ex.constraint = 'EMP_MANAGER_FK';+
+The following statement tries to place in ENABLE NOVALIDATE state two constraints on the employees table:+
+ALTER TABLE employees+
+ENABLE NOVALIDATE PRIMARY KEY+
+ENABLE NOVALIDATE CONSTRAINT emp_last_name_nn;+
+This statement has two ENABLE clauses:+
+*The first places a primary key constraint on the table in ENABLE NOVALIDATE state.+
+*The second places the constraint named emp_last_name_nn in ENABLE NOVALIDATE state.+
+In this case, Oracle Database enables the constraints only if both are satisfied by each row in the table. If any row violates either constraint, then the database returns an error and both constraints remain disabled.+
+Consider the foreign key constraint on the location_id column of the departments table, which references the primary key of the locations table. The following statement disables the primary key of the locations table:+
+ALTER TABLE locations+
+MODIFY PRIMARY KEY DISABLE CASCADE;+
+The unique key in the locations table is referenced by the foreign key in the departments table, so you must specify CASCADE to disable the primary key. This clause disables the foreign key as well.+
+"+
Hope That Helps.
Ogan