SQL> oradebug hanganalyze 3;
Hang Analysis in /oracle/admin/orcl/udump/orcl_ora_2622.trc
SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
-bash-3.2$ more /oracle/admin/orcl/udump/orcl_ora_2622.trc
/oracle/admin/orcl/udump/orcl_ora_2622.trc
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
ORACLE_HOME = /oracle/product/10.2.0/db_1
System name:    Linux
Node name:      truerhel5
Release:        2.6.18-164.el5
Version:        #1 SMP Tue Aug 18 15:51:48 EDT 2009
Machine:        x86_64
Instance name: orcl
Redo thread mounted by this instance: 1
Oracle process number: 21
Unix process pid: 2622, image: oracle@truerhel5 (TNS V1-V3)

*** SERVICE NAME:(SYS$USERS) 2010-08-07 21:11:10.818
*** SESSION ID:(145.36) 2010-08-07 21:11:10.818
*** 2010-08-07 21:11:10.818
==============
HANG ANALYSIS:
==============
Open chains found:
Chain 1 : : --每列的注解：分为cnode sid sess_srno proc_ptr ospid wait_event
    <0/148/27/0x70e5e4a8/2543/SQL*Net message from client>   --会话148(持锁会话）
 -- <0/146/84/0x70e5f478/2607/enq: TX - row lock contention> --会话146(等待锁会话），竞争事件为：row lock contention
Other chains found:
Chain 2 : :
    <0/144/108/0x70e5ccf0/2614/jobq slave wait>
Chain 3 : :
    <0/145/36/0x70e5fc60/2622/No Wait>
Chain 4 : :
    <0/150/2/0x70e623e8/2338/Streams AQ: waiting for time man>
Chain 5 : :
    <0/151/1/0x70e5ec90/2319/Streams AQ: qmn coordinator idle>
Chain 6 : :
    <0/158/7/0x70e61c00/2336/Streams AQ: qmn slave idle wait>
Extra information that will be dumped at higher levels:
[level  4] :   1 node dumps -- [REMOTE_WT] [LEAF] [LEAF_NW]
[level  5] :   5 node dumps -- [SINGLE_NODE] [SINGLE_NODE_NW] [IGN_DMP]
[level  6] :   1 node dumps -- [NLEAF]
[level 10] :  13 node dumps -- [IGN]
 
State of nodes
([nodenum]/cnode/sid/sess_srno/session/ospid/state/start/finish/[adjlist]/predecessor):
[143]/0/144/108/0x70f5dcf8/2614/SINGLE_NODE/1/2//none
[144]/0/145/36/0x70f5f130/2622/SINGLE_NODE_NW/3/4//none
[145]/0/146/84/0x70f60568/2607/NLEAF/5/8/[147]/none
[147]/0/148/27/0x70f62dd8/2543/LEAF/6/7//145
[149]/0/150/2/0x70f65648/2338/SINGLE_NODE/9/10//none
[150]/0/151/1/0x70f66a80/2319/SINGLE_NODE/11/12//none
[154]/0/155/1/0x70f6bb60/2315/IGN/13/14//none
[155]/0/156/1/0x70f6cf98/2313/IGN/15/16//none
[157]/0/158/7/0x70f6f808/2336/SINGLE_NODE/17/18//none
[159]/0/160/1/0x70f72078/2305/IGN/19/20//none
[160]/0/161/1/0x70f734b0/2303/IGN/21/22//none
[161]/0/162/1/0x70f748e8/2301/IGN/23/24//none
[162]/0/163/1/0x70f75d20/2299/IGN/25/26//none
[163]/0/164/1/0x70f77158/2297/IGN/27/28//none
[164]/0/165/1/0x70f78590/2295/IGN/29/30//none
[165]/0/166/1/0x70f799c8/2293/IGN/31/32//none
[166]/0/167/1/0x70f7ae00/2291/IGN/33/34//none
[167]/0/168/1/0x70f7c238/2289/IGN/35/36//none
[168]/0/169/1/0x70f7d670/2287/IGN/37/38//none
[169]/0/170/1/0x70f7eaa8/2285/IGN/39/40//none
====================
END OF HANG ANALYSIS
====================

其内容意思大概如下

cnode--节点代号,如果为rac,其值就存在,单节点的值为0

sid---session的sid

sess_srno---session的serial#

proc_ptr--系统进程指向的address

ospid ----进程号

wait_event---session的等待事件

转摘白大师部分节选
Hanganalyze是从Oracle 8i r2(8.1.6)开始提供的，其用法十分简单：

ALTER SESSION SET EVENTS 'immediate trace name HANGANALYZE level ';

或者

ORADEBUG hanganalyze

比如：

sql>oradebug setmypid;

sql>oradebug hanganalyze 3;

对于：

      10     Dump all processes (IGN state)
      5      Level 4 + Dump all processes involved in wait chains (NLEAF state)
      4      Level 3 + Dump leaf nodes (blockers) in wait chains (LEAF,LEAF_NW,IGN_DMP state)
      3      Level 2 + Dump only processes thought to be in a hang (IN_HANG state)
    1-2    Only HANGANALYZE output, no process dump at all

-bash-3.2$ sqlplus -prelim '/as sysdba' --通过prelim选项进入已经hang住（正常方式进不了sqlplus)的数据库

SQL*Plus: Release 10.2.0.1.0 - Production on Sat Aug 7 21:17:42 2010

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

SQL> show parameter sga
ORA-01012: not logged on

SQL> conn /as sysdba
Prelim connection established
SQL>