Thursday, 3 September 2009

Performance Tuning - Question 056.

What are the results of this query? (Choose all that apply.)
SELECT * FROM v$lockMINUSSELECT * FROM v$enqueue_lock/

A . All the DDL locks on the system

B. All user locks on the system

C. All DML locks on the system

D . Always 0 rows, since the views are synonymous

Explanation:

Answer B and C: The V$LOCK view shows all locks on the system. The V$ENQUEUE_LOCK view has the same columns as V$LOCK, except it displays all locks owned by enqueue state objects only. The difference is user and DML locks.

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