Databases Reference
In-Depth Information
SQL> SELECT p1, p1text, p2, p2text, wait_class, seconds_in_wait, state
FROM v$session_wait
WHERE event='enq: UL - contention';
P1 P1TEXT P2 P2TEXT WAIT_CLASS SECONDS_IN_WAIT STATE
---------- --------- ---------- ------ ----------- --------------- -------
1431044102 name|mode 1073741864 id Application 121 WAITING
SQL> SELECT name
FROM sys.dbms_lock_allocated la, v$session_wait sw
WHERE sw.event='enq: UL - contention'
AND la.lockid=sw.p2;
NAME
------------
MYAPP_MUTEX1
At the end of the day,
DBMS_LOCK
is no more, but also no less, than the ORACLE database
server's powerful enqueue mechanism externalized through a PL/SQL interface.
Source Code Depot
Table 16-2 lists this chapter's source files and their functionality.
Table 16-2.
SELECT FOR UPDATE SKIP LOCKED Source Code Depot
File Name
Functionality
create_queue_deq.sql
Creates an AQ queue table and attempts to dequeue a message
aq_enq.sql
Enqueues a message into a queue
dbms_lock.sql
Illustrates how to use the package
DBMS_LOCK
