oracle实用工具：oradebug

1 oradebug介绍

oradebug主要是给oracle支持人员使用的，尽管很早便有，但oracle官网很少有记载。他是个sql*plus命令行工具，有sysdba的权限就可以登入，无需特别设置。他可以被用于：

1）追踪进程，或者是你的，或者是外部的

2）确定进程往哪个trc文件写

3）转储：数据文件头、内部oracle结构等

4）挂起进程，暂时的

5）确定实例使用了哪些共享内存块和信号量

6）找出RAC实例使用了哪些互联地址和协议

7）修改SGA中的数据结构

2 oradebug使用步骤

1）启动sql*plus并以sysdba身份登入

2）连接到一个进程

3）设置一个事件或者进行诊断转储

4）检索trc文件名

5）与连接到的进程断开

3 oradebug命令介绍

sys@ORCL> oradebug help
HELP           [command]                 Describe one or all commands
SETMYPID                                 Debug current process
SETOSPID                          Set OS pid of process to debug
SETORAPID       ['force']        Set Oracle pid of process to debug
SHORT_STACK                              Dump abridged OS stack
DUMP             [addr]  Invoke named dump
DUMPSGA        [bytes]                   Dump fixed SGA
DUMPLIST                                 Print a list of available dumps
EVENT                              Set trace event in process
SESSION_EVENT                      Set trace event in session
DUMPVAR          [level]  Print/dump a fixed PGA/SGA/UGA variable
DUMPTYPE       
    Print/dump an address with type info
SETVAR             Modify a fixed PGA/SGA/UGA variable
PEEK             [level]      Print/Dump memory
POKE                   Modify memory
WAKEUP                           Wake up Oracle process
SUSPEND                                  Suspend execution
RESUME                                   Resume execution
FLUSH                                    Flush pending writes to trace file
CLOSE_TRACE                              Close trace file
TRACEFILE_NAME                           Get name of trace file
LKDEBUG                                  Invoke global enqueue service debugger
NSDBX                                    Invoke CGS name-service debugger
-G                Parallel oradebug command prefix
-R                Parallel oradebug prefix (return output
SETINST              Set instance list in double quotes
SGATOFILE               Dump SGA to file; dirname in double quotes
DMPCOWSGA       Dump & map SGA as COW; dirname in double quotes
MAPCOWSGA               Map SGA as COW; dirname in double quotes
HANGANALYZE    [level] [syslevel]        Analyze system hang
FFBEGIN                                  Flash Freeze the Instance
FFDEREGISTER                             FF deregister instance from cluster
FFTERMINST                               Call exit and terminate instance
FFRESUMEINST                             Resume the flash frozen instance
FFSTATUS                                 Flash freeze status of instance
SKDSTTPCS                Helps translate PCs to names
WATCH          
    Watch a region of memory
DELETE          watchpoint     Delete a watchpoint
SHOW            watchpoints        Show  watchpoints
CORE                                     Dump core without crashing process
IPC                                      Dump ipc information
UNLIMIT                                  Unlimit the size of the trace file
PROCSTAT                                 Dump process statistics
CALL            [arg1] ... [argn]  Invoke function with arguments

4 连接到一个进程

在oradebug命令执行之前，你必须加入一个目标进程。这个目标进程有如下3种情况：

命令	目的
oradebug setmypid	连接到为你的sql*plus提供服务的进程
oradebug setorapid pid	连接到一个外部服务进程，且pid=v$process.pid
oradebug setospid spid	连接到一个外部服务进程，且spid=v$process.pid

1) setmypid

sys@ORCL> oradebug setmypid
Statement processed.
sys@ORCL> oradebug unlimit
Statement processed.
sys@ORCL> oradebug event 10046 trace name context forever,level 8 
Statement processed.
sys@ORCL> select * from hr.departments where department_id=10;

DEPARTMENT_ID DEPARTMENT_NAME                MANAGER_ID LOCATION_ID
------------- ------------------------------ ---------- -----------
           10 Administration                        200        1700

sys@ORCL> oradebug tracefile_name
/u01/app/oracle/admin/orcl/udump/orcl_ora_5234.trc
sys@ORCL> oradebug event 10046 trace name context off
Statement processed.

2）setospid（spid操作）

sys@ORCL> host top

top - 15:14:20 up 47 min,  2 users,  load average: 0.22, 0.20, 0.26
Tasks: 171 total,   2 running, 168 sleeping,   0 stopped,   1 zombie
Cpu(s):  1.3%us,  1.3%sy,  0.0%ni, 97.4%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:    678912k total,   671192k used,     7720k free,    16672k buffers
Swap:        0k total,        0k used,        0k free,   401584k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                    
 5874 oracle    15   0  2444 1084  828 R  1.6  0.2   0:00.47 top                                        
 4781 root      15   0 53900  11m 6076 S  0.7  1.7   1:00.13 Xorg                                       
 5168 oracle    16   0  491m  17m  15m S  0.3  2.6   0:02.41 oracle                                     
sys@ORCL> oradebug setospid 5168
Oracle pid: 7, Unix process pid: 5168, image: [email protected] (CKPT)

3）setorapid（pid操作）

sys@ORCL> select sid from v$mystat where rownum=1;                

       SID
----------
       159

sys@ORCL> select pid,spid from v$process p,v$session s where s.sid=159 and s.paddr=p.addr;

       PID SPID
---------- ------------
        15 5234

sys@ORCL> oradebug setorapid 15
Statement processed.
sys@ORCL> oradebug tracefile_name
/u01/app/oracle/admin/orcl/udump/orcl_ora_5234.trc
sys@ORCL> oradebug event 10046 trace name context off
Statement processed.

注意，在OEM的top session也可以等价实现上述效果，即：确定哪些数据库会话消耗了较多的资源

5 oradebug IPC

查看共享信息的内存的命令是ipcs [-m|-s|-q]。默认会列出共享内存、信号量，队列信息，-m列出共享内存，-s列出共享信号量，-q列出共享队列

sys@ORCL> host ipcs -m | grep ora
0xbe3bb918 5439503    oracle    640        419438592  20     
sys@ORCL> oradebug setmypid
Statement processed.
sys@ORCL> oradebug ipc
Information written to trace file.
sys@ORCL> oradebug tracefile_name
/u01/app/oracle/admin/orcl/udump/orcl_ora_5234.trc
sys@ORCL> oradebug event 10046 trace name context off
Statement processed.

当一台电脑的资源有限时，失败的实例占用共享内存和信号量会导致资源紧张，从而使得新的oracle实例无法启动。

清除命令是ipcrm [-m|-s|-q] id。
-m 删除共享内存，-s删除共享信号量，-q删除共享队列
如：ipcrm -m 5439503

6oradebug SHORT_STACK

如果一个程序挂起，那么程序调用栈就可以显示它在调用路径中的哪一步挂起

sys@ORCL> oradebug setospid 5180
Oracle pid: 13, Unix process pid: 5180, image: [email protected] (D000)
sys@ORCL> oradebug short_stack
ksdxfstk()+19<-ksdxcb()+1321<-sspuser()+81<-__kernel_vsyscall()+2<-ntevpque()+112<-ntevque()+606<-nsevwait()+821<-ksnwait()+111<-ksliwat()+770<-kslwaitns()+29<-

kskthbwt()+370<-kslwait()+57<-kmdmai()+1797<-kmmrdp()+432<-opirip()+1191<-opidrv()+864<-sou2o()+113<-opimai_real()+353<-main()+111<-__libc_start_main()+220
sys@ORCL> oradebug event 10046 trace name context off
Statement processed.

当前的调用步骤在输出的顶部

7 诊断转储

可转储类型如下：

sys@ORCL> oradebug dumplist
EVENTS
TRACE_BUFFER_ON
TRACE_BUFFER_OFF
HANGANALYZE
LATCHES
PROCESSSTATE
SYSTEMSTATE
INSTANTIATIONSTATE
.........

下面举例两个：

1）controlf

sys@ORCL> oradebug setmypid
Statement processed.
sys@ORCL> oradebug dump controlf 10
Statement processed.
sys@ORCL> oradebug tracefile_name
/u01/app/oracle/admin/orcl/udump/orcl_ora_5234.trc

2）events

这不是真正的转储，events只是将激活的事件写入trc文件。如果你不能确定一个会话、进程或者实例中哪个事件是活动的，下面有一种很好的方式去查询：

sys@ORCL> alter session set events '10046 trace name context forever,level 8';

Session altered.

sys@ORCL> alter session set events '4031 trace name heapdump level 3';

Session altered.

sys@ORCL> oradebug setmypid
Statement processed.
sys@ORCL> oradebug dump events 1
Statement processed.
sys@ORCL> oradebug tracefile_name
/u01/app/oracle/admin/orcl/udump/orcl_ora_5234.trc
sys@ORCL> oradebug event 10046  trace name context off
Statement processed.

oradebug dump events的级别和范围

级别	事件范围	使用的命令
1	会话	alter session
2	进程	oradebug event
4	实例	alter system

8 小结

oradebug对于解决问题和诊断性能是必不可少的工具。本文只是讲述了一些最常见的命令，还有更多的功能，比如RAC环境下调用全局队列服务调试器的

oradebug lkdebug命令。