Oracle事件10704可以帮助我们了解队列Enqueue的使用情况，使用方法如下:
[oracle@rh2 bdump]$ oerr ora 10704
10704, 00000, "Print out information about what enqueues are being obtained"
// *Cause: When enabled, prints out arguments to calls to ksqcmi and
// ksqlrl and the return values.
// *Action: Level indicates details:
// Level: 1-4: print out basic info for ksqlrl, ksqcmi
// 5-9: also print out stuff in callbacks: ksqlac, ksqlop
// 10+: also print out time for each line
SQL> oradebug setmypid;
Statement processed.
SQL> oradebug event 10704 trace name context forever,level 10;
Statement processed.
SQL> lock table tm in share mode;
Table(s) Locked.
SQL> oradebug tracefile_name;
/s01/admin/G10R2/udump/g10r2_ora_28400.trc
ksqgtl *** CU-9fec6e30-00000000 mode=6 flags=0x10 timeout=300 ***
ksqgtl: no transaction
ksqgtl: use existing ksusetxn DID
ksqgtl:
ksqlkdid: 0001-0017-00000008
*** 2011-05-07 21:17:16.139
*** ksudidTrace: ksqgtl
ksusesdi: 0000-0000-00000000
ksusetxn: 0001-0017-00000008
ksqgtl: RETURNS 0
*** 2011-05-07 21:17:16.160
ksqrcl: CU,9fec6e30,0
ksqrcl: returns 0
*** 2011-05-07 21:17:23.884
ksqgtl *** CU-9fec69f8-00000000 mode=6 flags=0x10 timeout=300 ***
ksqgtl: no transaction
ksqgtl: use existing ksusetxn DID
ksqgtl:
ksqlkdid: 0001-0017-00000008
*** 2011-05-07 21:17:23.884
*** ksudidTrace: ksqgtl
ksusesdi: 0000-0000-00000000
ksusetxn: 0001-0017-00000008
ksqgtl: RETURNS 0
*** 2011-05-07 21:17:23.898
ksqrcl: CU,9fec69f8,0
ksqrcl: returns 0
*** 2011-05-07 21:17:23.899
ksqgtl *** TM-0000d06b-00000000 mode=4 flags=0x401 timeout=21474836 ***
ksqgtl: xcb=0xa69d0a00, ktcdix=2147483647, topxcb=0xa69d0a00
ktcipt(topxcb)=0x0
*** 2011-05-07 21:17:23.899
ksucti: init txn DID from session DID 0001-0017-00000008
ksqgtl:
ksqlkdid: 0001-0017-00000008
*** 2011-05-07 21:17:23.899
*** ksudidTrace: ksqgtl
ktcmydid(): 0001-0017-00000008
ksusesdi: 0000-0000-00000000
ksusetxn: 0001-0017-00000008
ksqgtl: RETURNS 0
该10704事件可以配合10046事件一起诊断异常的队列锁问题，记以录之！
本文转自maclean_007 51CTO博客，原文链接:http://blog.51cto.com/maclean/1276758
