1. SQL> ! ps -ef | grep smon       
   
2.   oracle 766348      1   0 14:29:34      -  0:02 ora_smon_testdb 
   
3.   oracle 398618 128480   0 16:51:16  pts/3  0:00 /usr/bin/bash -c  ps -ef | grep smon 
   
4.   oracle 157498 398618   0 16:51:16  pts/3  0:00 grep smon 
   
5. 
   
6. SQL> oradebug setospid 766348
   
7. Oracle pid: 30, Unix process pid: 766348, image: oracle@sxffdb2 (SMON)
   
8. SQL> oradebug tracefile_name
   
9. /u01/oracle/admin/testdb/bdump/testdb_smon_766348.trc
   
10. SQL> ! ls -ltr /u01/oracle/admin/testdb/bdump/testdb_smon_766348.trc
    
11. -rw-r-----    1 oracle   oinstall       1471 Aug 01 16:51 /u01/oracle/admin/testdb/bdump/testdb_smon_766348.trc
    
12. 
    
13. SQL> ! rm -rf /u01/oracle/admin/testdb/bdump/testdb_smon_766348.trc
    
14. 
    
15. SQL> oradebug close_trace
    
16. Statement processed.
    
17. SQL> ! ls -ltr /u01/oracle/admin/testdb/bdump/testdb_smon_766348.trc
    
18. ls: 0653-341 The file /u01/oracle/admin/testdb/bdump/testdb_smon_766348.trc does not exist.
    
19. 
    
20. SQL> oradebug event 10046 trace name context forever,level 1;
    
21. Statement processed.
    
22. SQL> ! ls -ltr /u01/oracle/admin/testdb/bdump/testdb_smon_766348.trc
    
23. -rw-r-----    1 oracle   oinstall        651 Aug 01 16:53 /u01/oracle/admin/testdb/bdump/testdb_smon_766348.trc

清理打开的TRC文件：

1. [oracle@testdb bdump]$ ls -ltr  testdb_smon_766348.trc
   
2. -rw-r-----    1 oracle   oinstall    1766052 Aug 01 17:25 testdb_smon_766348.trc
   
3. [oracle@sxffdb2 bdump]$ cat /dev/null > testdb_smon_766348.trc --代替rm
   
4. [oracle@sxffdb2 bdump]$ ls -ltr testdb_smon_766348.trc
   
5. -rw-r-----    1 oracle   oinstall         10 Aug 01 17:26 testdb_smon_766348.trc
   
6. [oracle@testdb bdump]$

较全面的步骤

一.  Oradebug 命令 帮助文档
SYS@dave2(db2)> oradebug help


1.1 TRACEFILE_NAME command
This command prints the name of the current trace file e.g.
SQL>oradebug tracefile_name
For example
    /export/home/admin/SS92003/udump/ss92003_ora_14917.trc
This command does not work on Windows 2000 (Oracle 9.2)
 

1.2 UNLIMIT command
       In Oracle 8.1.5 and below the maximum size of the trace file is restricted by default. This means that large dumps (LIBRARY_CACHE, BUFFERS) may fail.

To remove the limitation on the size of the trace file use
SQL>oradebug unlimit
       In Oracle 8.1.6 and above the maximum size of the trace file defaults to UNLIMITED

 
1.3 FLUSH command
To flush the current contents of the trace buffer to the trace file use
SQL>oradebug flush
 

1.4 CLOSE_TRACE command
To close the current trace file use
SQL>oradebug close_trace


二.  追踪进程
如果是系统的进程ID，可以使用oradebug setospid id.
如果是根据Oracle ID，可以使用oradebug setorapid id 来追踪。
 

2.1 查询进程ID
可以查询Linux系统的pid或是oracle自己的pid：
SYS@dave2(db2)> select a.username,a.sid ,a.serial#,b.spid  from v$session a,v$process b where a.paddr=b.addr;
 

USERNAME    SID    SERIAL# SPID
---------- ---------- ---------- ------------
SYS               159       1702 27028
 

查询spid
SYS@dave2(db2)> select pid,spid,username from v$process;



       PID SPID         USERNAME
--------- ------------ ----------
        18 27028        oracle



v$process 下的pid 是Oracle 的ID。spid 是系统的ID。

 
 

2.2 设定追踪
SYS@dave2(db2)> oradebug setospid 27028  -- 根据系统ID
Oracle pid: 18, Unix process pid: 27028, image: oracledave2@db2
 

或者使用，他们是一样的：
SYS@dave2(db2)> oradebug setorapid 18   --根据Oracle ID
Unix process pid: 27028, image: oracledave2@db2
 

2.3  dump 相关文件信息
       指定为SID 之后，就可以使用dump 将相关的信息，这些dump 内容很多。 可以使用dumplist 把所有的dump 可列出来。
 

具体使用，可以参考：
       http://psoug.org/reference/oradebug.html
 

SYS@dave2(db2)> oradebug dumplist
EVENTS
TRACE_BUFFER_ON
TRACE_BUFFER_OFF
HANGANALYZE
LATCHES
PROCESSSTATE
SYSTEMSTATE
INSTANTIATIONSTATE
REFRESH_OS_STATS
.......
CONTEXTAREA
AWR_FLUSH_TABLE_OFF
ASHDUMP
MMON_TEST
SYS@dave2(db2)>
 

       在这些dump选项中，大部分都有2，4，6，8，10，12等几个跟踪级别。在使用的时候要根据具体的情况来选择级别，不同级别的影响不一样。

 

2.3.1 获得系统状态
如果为了获取全面一点的信息，可以使用Level 10。


 

SYS@dave2(db2)> oradebug setospid 27028
Oracle pid: 18, Unix process pid: 27028, image: oracledave2@db2
SYS@dave2(db2)> oradebug unlimit
Statement processed.
SYS@dave2(db2)> oradebug dump systemstate 10
Statement processed.
SYS@dave2(db2)> oradebug TRACEFILE_NAME
/u01/app/oracle/admin/dave2/udump/dave2_ora_27028.trc

SYS@dave2(db2)> oradebug close_trace
Statement processed.

[oracle@db2 ~]$ tail -50 /u01/app/oracle/admin/dave2/udump/dave2_ora_27028.trc
              last process to post me: none
              last post sent: 0 0 0
              last post sent-location: No post
              last process posted by me: none
    (latch info) wait_event=0 bits=0
    Process Group: DEFAULT, pseudo proc: 0x2e24c604
    O/S info: user: , term: , ospid:
    OSD pid info: Unix process pid: 0, image: PSEUDO
Dump of memory from 0x2E207970 to 0x2E207AF4
2E207970 00000000 00000000 00000000 00000000  [................]
        Repeat 23 times
2E207AF0 00000000                             [....]          
NO DETACHED BRANCHES.
NO DETACHED NETWORK CONNECTIONS.
CLEANUP STATE OBJECTS:
----------------------------------------
SO: 0x2e03465c, type: 1, owner: (nil), flag: INIT/-/-/0x00
(cleanup state object) description: instance enqueue anchor state
latch: 0x2000502c
  ----------------------------------------
  SO: 0x2e3b9bc0, type: 5, owner: 0x2e03465c, flag: INIT/-/-/0x00
  (enqueue) TA-00000006-00000001        DID: 0001-000F-
  lv: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  flag:
  res: 2d8362f4, mode: X, prv: 2d8362fc, own: 0, sess: 0

SO: 0x2e0346a0, type: 1, owner: (nil), flag: INIT/-/-/0x00
(cleanup state object) description: switchable channel handle anch
latch: 0x200059cc
  ----------------------------------------
  SO: 0x2d87ac7c, type: 11, owner: 0x2e0346a0, flag: INIT/-/-/0x00
  (broadcast handle) flag: (c2) ACTIVE SUBSCRIBER, owner: (nil),
                     event: 1, last message event: 1,
                    last message waited event: 1, messages read: 0
                     channel: (0x2d8827f0) KPON channel
                              scope: 2, event: 1, last mesage event: 0,
                              publishers/subscribers: 0/1,
                              messages published: 0
----------------------------------------
SO: 0x2e0346e4, type: 1, owner: (nil), flag: INIT/-/-/0x00
(cleanup state object) description: TT shared object cleanup SO
latch: 0x2000dc98
----------------------------------------
SO: 0x2e034728, type: 1, owner: (nil), flag: INIT/-/-/
(cleanup state object) description: SS shared object cleanup
latch:
END OF SYSTEM
*** 2011-06-04 05:28:17.
Received ORADEBUG command 'TRACEFILE_NAME' from process Unix process pid: 27042,
*** 2011-06-04 05:32:21.241

Received ORADEBUG command 'close_trace' from process Unix process pid: 27042, image:

[oracle@db2 ~]$

 

 

       如果系统hung的时候，systemstate基本等同于hanganalyze，可以用于诊断system hung

 

关于hanganalyze 参考：

       Oracle HANGANALYZE 功能诊断 DB hanging

       http://blog.csdn.net/tianlesoftware/archive/2011/04/13/6321961.aspx

 

 

2.3.2  获得某个进程状态

SYS@dave2(db2)> oradebug setospid 27028

Oracle pid: 18, Unix process pid: 27028, image: oracledave2@db2

-- 注意，这里必须是Oracle 的进程

SYS@dave2(db2)> oradebug dump processstate 10

Statement processed.

SYS@dave2(db2)> oradebug TRACEFILE_NAME

/u01/app/oracle/admin/dave2/udump/dave2_ora_27028.trc

 

SQL> oradebug setospid 3188

2.3.3 获得进程的错误信息状态

SYS@dave2(db2)> oradebug dump errorstack 3;     (会dump到TRC 文件一些报告,但难看懂)

Statement processed.

SYS@dave2(db2)> oradebug TRACEFILE_NAME

/u01/app/oracle/admin/dave2/udump/dave2_ora_27028.trc

 

 

三.  Trace  SQL

3.1 Trace a session SQL

3.1.1 使用DBMS_SYSTEM包

SQL>select a.username,a.sid ,a.serial#,b.spid from v$session a,v$process b  where a.paddr=b.addr;

 

USERNAME                              SID    SERIAL# SPID
------------------------------ ---------- ---------- -------------------- ---------- ---------- -------
SCOTT                                 143          6    3260

 

--开启对该进程的trace，记录在trace文件中:

执行SQL> execute dbms_system.set_sql_trace_in_session(143,6,true);

 

--关闭追踪

执行SQL> execute dbms_system.set_sql_trace_in_session(143,6,false);

 

3.1.2使用oradebug

SQL> oradebug setospid 3260  --进程的spid

SQL> oradebug event 10046 trace name context forever,level 4

-- 取消追踪使用

SQL> oradebug event 10046 trace name context off

已处理的语句
(此步是针对oradebug event 10046 trace name context forever,level 4 的,

 执行这步TRC 日志就能看到在不断写入

oradebug event 10046 trace name context off这步不执行,

而退出SQLPLUS 即SQL> EXIT;或SQL> oradebug close_trace时TRC日志仍在写入,

可重新登陆执行oradebug setospid SPID号,

再SQL>oradebug event 10046 trace name context forever,level [0-10],

再执行SQL>oradebug event 10046 trace name context off

就不会再写入日志)

 

3.1.3 Tracing errors use oradebug

例如要追踪能造成ORA-0094/952错误的会话，

SQL> oradebug event 942 trace name errorstack level 3

SQL> oradebug event 952 trace name errorstack level 3

 

四.  Events 事件

 

关于Events,  eygle 的blog有说明，参考：

http://www.eygle.com/digest/2008/04/oracle_internal_events_introdu.html

 

Events可以在Instance一级Enabled,主要是在init.ora文件中做操作:

        event='event trace name context forever, level level';

 

 一次可以Enable多个事件,可以用以下两种方式:

（1） 用一个冒号隔开

       event = "10248 trace name context forever, level 10:10249 trace name context forever, level 10"

（2） 两个Events分开写

      event="10248 trace name context forever, level 10"

      event="10249 trace name context forever, level 10"

       #一些版本的Oracle，event要一样的大小写

 

instance级别event：

enable:

      SQL>alter system set events 'event trace name context forever, level level';

Disable：

     SQL>alter system set events 'event trace name context off';

 

Session 级别Event：

--Enable:

      SQL>alter session set events 'event trace name context forever, levellevel';

--Disable:

       SQL>alter session set events 'event trace name context off';

 

Oradebug  Events：

--Process中Enable:

SQL>oradebug event event trace name context forever, level level

 

--进程中Enable:

SQL>oradebug setorapid 8(pid进程号)

SQL>oradebug event event trace name context forever, level level

 

 --Disable:

SQL>oradebug event event trace name context off

 

Session Events:

--Enable:

 SQL>oradebug session_event event trace name context forever, level level

--Disable:

SQL>oradebug session_event event trace name context off

 

使用DBMS_SYSTEM.SETEV包来实现Enable和Disable

先从V$session视图中获得SID和Serial#

--Enable：

SQL>execute dbms_system.set_ev(sid,serial#,event,level, '')

SQL>execute dbms_system.set_ev (9,29,10046,8,'');

--Disable则将level改为0

SQL> execute dbms_system.set_ev (9,29,10046,0,'');

 

 

五.  Other Data

From：

http://www.juliandyke.com/Diagnostics/Tools/ORADEBUG/Introduction.html

 

5.1 DUMP command

To perform a dump use

SQL>oradebug dump dumpname level

For example for a level 4 dump of the library cache use

SQL>oradebug setmypid

SQL>oradebug dump library_cache 4

 

5.2 EVENT command

To set an event in a process use

SQL>oradebug event event trace name context forever, level level

For example to set event 10046, level 12 in Oracle process 8 use

SQL>oradebug setorapid 8

SQL>oradebug event 10046 trace name context forever, level 12

 

5.3 SESSION_EVENT command

To set an event in a session use

SQL>oradebug session_event event trace name context forever, level level

For example

SQL>oradebug session_event 10046 trace name context forever, level 12

 

5.4 DUMP SGA

To dump the fixed SGA use

SQL>oradebug dumpsga

 

5.5 DUMPVAR

To dump an SGA variable use

SQL>oradebug dumpvar sga variable_name

e.g.

SQL>oradebug dumpvar sga kcbnhb

       which returns the number of hash buckets in the buffer cache. The names of SGA variables can be found in X$KSMFSV.KSMFSNAM. Variables in this view are suffixed with an underscore e.g.  kcbnhb_

 

5.6 PEEK

To peek memory locations use

SQL>oradebug peek address length

where address can be decimal or hexadecimal and length is in bytes

For example

SQL>ORADEBUG PEEK 0x20005F0C 12

returns 12 bytes starting at location 0x20005f0c

 

5.7 POKE

To poke memory locations use

SQL>ORADEBUG POKE address length value

where address and value can be decimal or hexadecimal and length is in bytes

 

For Example

SQL>ORADEBUG POKE 0x20005F0C 4 0x46495845

SQL>ORADEBUG POKE 0x20005F10 4 0x44205349

SQL>ORADEBUG POKE 0x20005F14 2 0x5A45

 -- WARNING Do not use the POKE command on a production system

 

5.8 IPC

To dump information about operating system shared memory and semaphores configuration use the command

SQL>ORADEBUG IPC

This command does not work on Windows NT or Windows 2000 (Oracle 9.2)

On Solaris, similar information can be obtained using the operating system command

    ipcs -b

 

5.9 Dumping the SGA

In some versions it is possible to dump the entire SGA to a file

Freeze the instance using

SQL>oradebug ffbegin

 

Dump the SGA to a file using

SQL>oradebug sgatofile directory

 

Unfreeze the instance using

SQL>oradebug ffresumeinst

参考blog.csdn.net/tianlesoftware/article/details/6525628