oradebug是SQL*PLUS工具，只要有SYSDBA权限就可以使用，不用做特别设置，但其功能很强大，是每个从事oracle工作人员必不可少的利器。
下面就介绍一些常用功能：
1：获得trace文件的名字和位置
SQL> select * from v$version; BANNER ---------------------------------------------------------------- Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Prod PL/SQL Release 10.2.0.4.0 - Production CORE 10.2.0.4.0 Production TNS for Linux: Version 10.2.0.4.0 - Production NLSRTL Version 10.2.0.4.0 - Production SQL> alter session set events 'immediate trace name controlf level 12'; Session altered. SQL> oradebug setmypid Statement processed. SQL> oradebug tracefile_name /u01/oracle/admin/gdf/udump/gdf_ora_1961.trc SQL>
2：诊断转储
可以转储的类型：
SQL> oradebug dumplist EVENTS TRACE_BUFFER_ON TRACE_BUFFER_OFF HANGANALYZE LATCHES PROCESSSTATE SYSTEMSTATE INSTANTIATIONSTATE REFRESH_OS_STATS CROSSIC CONTEXTAREA HEAPDUMP HEAPDUMP_ADDR POKE_ADDRESS POKE_LENGTH POKE_VALUE POKE_VALUE0 GLOBAL_AREA MEMORY_LOG REALFREEDUMP FLUSH_JAVA_POOL POOL_SIMULATOR PGA_DETAIL_GET PGA_DETAIL_DUMP PGA_DETAIL_CANCEL MODIFIED_PARAMETERS EVENT_TSM_TEST ERRORSTACK CALLSTACK HANGANALYZE_PROC TEST_STACK_DUMP TEST_GET_CALLER RECORD_CALLSTACK EXCEPTION_DUMP BG_MESSAGES ENQUEUES KSTDUMPCURPROC KSTDUMPALLPROCS SIMULATE_EOV KSFQP_LIMIT KSKDUMPTRACE DBSCHEDULER LDAP_USER_DUMP LDAP_KERNEL_DUMP DUMP_ALL_OBJSTATS DUMPGLOBALDATA HANGANALYZE_GLOBAL GES_STATE OCR CSS CRS SYSTEMSTATE_GLOBAL CREATE_DUMMY_REQUEST MMAN_ALLOC_MEMORY MMAN_CREATE_REQUEST MMAN_CREATE_IMM_REQUEST DUMP_ALL_COMP_GRANULE_ADDRS DUMP_ALL_COMP_GRANULES DUMP_ALL_REQS DUMP_TRANSFER_OPS DUMP_ADV_SNAPSHOTS ADJUST_SCN NEXT_SCN_WRAP CONTROLF FLUSH_CACHE FULL_DUMPS BUFFERS RECOVERY SET_TSN_P1 BUFFER PIN_BLOCKS BC_SANITY_CHECK PIN_RANDOM_BLOCKS SET_NBLOCKS CHECK_ROREUSE_SANITY DUMP_PINNED_BUFFER_HISTORY REDOLOGS LOGHIST ARCHIVE_ERROR REDOHDR LOGERROR OPEN_FILES DATA_ERR_ON DATA_ERR_OFF BLK0_FMTCHG UPDATE_BLOCK0_FORMAT TR_SET_BLOCK TR_SET_ALL_BLOCKS TR_SET_SIDE TR_CRASH_AFTER_WRITE TR_READ_ONE_SIDE TR_CORRUPT_ONE_SIDE TR_RESET_NORMAL TEST_DB_ROBUSTNESS LOCKS GC_ELEMENTS FILE_HDRS KRB_CORRUPT_INTERVAL KRB_CORRUPT_SIZE KRB_CORRUPT_REPEAT KRB_PIECE_FAIL KRB_OPTIONS KRB_FAIL_INPUT_FILENO KRB_SIMULATE_NODE_AFFINITY KRB_TRACE KRB_BSET_DAYS KRB_SET_TIME_SWITCH KRBMRSR_LIMIT KRBMROR_LIMIT KRC_TRACE KRA_OPTIONS KRA_TRACE FBTAIL FBINC FBHDR FLASHBACK_GEN DROP_SEGMENTS KTPR_DEBUG TREEDUMP LONGF_CREATE ROW_CACHE LIBRARY_CACHE CURSORDUMP CURSORTRACE CURSOR_STATS SHARED_SERVER_STATE JAVAINFO KXFPCLEARSTATS KXFPDUMPTRACE KXFPBLATCHTEST KXFXSLAVESTATE KXFXCURSORSTATE WORKAREATAB_DUMP KUPPLATCHTEST OBJECT_CACHE SAVEPOINTS RULESETDUMP RULESETDUMP_ADDR OLAP_DUMP SELFTESTASM IOERREMUL ALRT_TEST AWR_TEST AWR_FLUSH_TABLE_ON AWR_FLUSH_TABLE_OFF ASHDUMP MMON_TEST SQL>
由于可转储类型太多，鉴于篇幅，现举例常用的几个，其他类似。
a：controlf
SQL> oradebug setmypid Statement processed. SQL> oradebug dump controlf 12 Statement processed. SQL> oradebug tracefile_name /u01/oracle/admin/gdf/udump/gdf_ora_1961.trc
效果与以下语句一样
alter session set events 'immediate trace name controlf level 12';
b：redo log header
SQL> oradebug setmypid Statement processed. SQL> oradebug dump redohdr 10 Statement processed. SQL> oradebug tracefile_name /u01/oracle/admin/gdf/udump/gdf_ora_2198.trc SQL> !
效果同以下语句一样：
alter session set events 'immediate trace name redohdr level 10'
其他类似。
下面举一个具体的案例来说明oradebug的功能：
追踪SMON：
[oracle@edhatGRA ~]$ ps -ef | grep smon oracle 1947 1 0 17:31 ? 00:00:01 ora_smon_gdf oracle 2300 2222 0 19:01 pts/0 00:00:00 grep smon [oracle@edhatGRA ~]$ sqlplus /nolog SQL*Plus: Release 10.2.0.4.0 - Production on Sun May 5 19:01:23 2013 Copyright (c) 1982, 2007, Oracle. All Rights Reserved. SQL> conn / as sysdba Connected. SQL> oradebug setospid 1947 Oracle pid: 8, Unix process pid: 1947, image: oracle@edhatGRA (SMON) SQL> oradebug event 10500 trace name context forever,level 10 Statement processed. SQL> oradebug tracefile_name /u01/oracle/admin/gdf/bdump/gdf_smon_1947.trc SQL>
打开该文件
[oracle@edhatGRA ~]$ vi /u01/oracle/admin/gdf/bdump/gdf_smon_1947.trc
/u01/oracle/admin/gdf/bdump/gdf_smon_1947.trc Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Production With the Partitioning, OLAP, Data Mining and Real Application Testing options ORACLE_HOME = /u01/oracle/10g System name: Linux Node name: edhatGRA Release: 2.6.32-71.el6.i686 Version: #1 SMP Wed Sep 1 01:26:34 EDT 2010 Machine: i686 Instance name: gdf Redo thread mounted by this instance: 1 Oracle process number: 8 Unix process pid: 1947, image: oracle@edhatGRA (SMON) *** 2013-05-05 19:02:19.833 *** SERVICE NAME:(SYS$BACKGROUND) 2013-05-05 19:02:19.832 *** SESSION ID:(164.1) 2013-05-05 19:02:19.832 Received ORADEBUG command 'event 10500 trace name context forever,level 10' from process Unix process pid: 2304, image: *** 2013-05-05 19:02:19.833 SMON: system monitor process posted *** 2013-05-05 19:02:19.833 SMON: Posted too frequently, trans recovery disabled. Received ORADEBUG command 'tracefile_name' from process Unix process pid: 2304, image: *** 2013-05-05 19:02:29.420 SMON: system monitor process posted *** 2013-05-05 19:02:29.420 SMON: Posted too frequently, trans recovery disabled.
结合oracle的事件，oradebug可发挥强大功能，为你解决问题，深入理解oracle内部原理，提供有益的帮助。
3：总结
oradebug对于学习oracle，解决问题，诊断问题是必不可少的工具，本文只是oradebug的入门，更多功能请参阅相关文档。本人提供一些链接：
a：http://www.dba-oracle.com/t_oradebug_tips.htm
b: http://www.juliandyke.com/Diagnostics/Tools/ORADEBUG/ORADEBUG.html
c：http://www.orafaq.com/wiki/Oradebug