oradebug使用详解

oradebug使用详解
Tools
ORADEBUG
ORADEBUG is an undocumented debugging utility supplied with Oracle For more general information see ORADEBUG introduction
In Oracle 9.2 commands include
HELP
SETMYPID
SETORAPID
SETOSPID
TRACEFILE_NAME
UNLIMIT
FLUSH
CLOSE_TRACE
SUSPEND
RESUME
WAKEUP
DUMPLIST
DUMP
EVENT
SESSION_EVENT
DUMPSGA
DUMPVAR
PEEK
POKE
IPC
Dumping the SGA
HELP command
The ORADEBUG HELP command lists the commands available within ORADEBUG
These vary by release and platform. Commands appearing in this help do not necessarily work for the release/platform on which the database is running
For example in Oracle 9.2.0.1 (Windows 2000) the command
ORADEBUG HELP
returns the following
SETMYPID command
Before using ORADEBUG commands, a process must be selected. Depending on the commands to be issued, this can either be the current process or another process
Once a process has been selected, this will be used as the ORADEBUG process until another process is selected
The SETMYPID command selects the current process as the ORADEBUG process
For example
ORADEBUG SETMYPID
ORADEBUG SETMYPID can be used to select the current process to run systemwide commands such as dumps
Do not use ORADEBUG SETMYPID if you intend to use the ORADEBUG SUSPEND command SETORAPID command
Before using ORADEBUG commands, a process must be selected. Depending on the commands to be issued, this can either be the current process or another process
Once a process has been selected, this will be used as the ORADEBUG process until another process is selected
The SETORAPID command selects another process using the Oracle PID as the ORADEBUG process
The syntax is
ORADEBUG SETORAPID pid
where pid is the Oracle process ID of the target process For example
ORADEBUG SETORAPID 9
The Oracle process id for a process can be found in V$PROCESS.PID
To obtain the Oracle process ID for a foreground process use
SELECT pid FROM v$process
WHERE addr =
(
SELECT paddr FROM v$session
WHERE sid = DBMS_SUPPORT.MYSID
);
Alternatively, if the DBMS_SUPPORT package is not available use
SELECT pid FROM v$process
WHERE addr =
(
SELECT paddr FROM v$session
WHERE sid =
(
SELECT sid FROM v$mystat WHERE ROWNUM = 1
)
);
To obtain the process ID for a background process e.g. SMON use
SELECT pid FROM v$process
WHERE addr =
(
SELECT paddr FROM v$bgprocess
WHERE name = 'SMON'
);
To obtain the process ID for a dispatcher process e.g. D000 use
SELECT pid FROM v$process
WHERE addr =
(
SELECT paddr FROM v$dispatcher
WHERE name = 'D000'
);
To obtain the process ID for a shared server process e.g. S000 use
SELECT pid FROM v$process
WHERE addr =
(
SELECT paddr FROM v$shared_server
WHERE name = 'S000'
);
To obtain the process ID for a job queue process e.g. job 21 use
SELECT pid FROM v$process
WHERE addr =
(
SELECT paddr FROM v$session
WHERE sid =
(
SELECT sid FROM dba_jobs_running WHERE job = 21
)
);
To obtain the process ID for a parallel execution slave e.g. P000 use
SELECT pid FROM v$px_process
WHERE server_name = 'P000';
SETOSPID command
Before using ORADEBUG commands, a process must be selected. Depending on the commands to be issued, this can either be the current process or another process
Once a process has been selected, this will be used as the ORADEBUG process until another process is selected
The SETOSPID command selects the another process using the operating system PID as the ORADEBUG process
The syntax is
ORADEBUG SETOSPID pid
where pid is the operating system process ID of the target process For example ORADEBUG SETOSPID 34345
The operating system process ID is the PID on Unix systems and the thread number on Windows NT/2000 systems
On Unix the PID of interest may have been identified using a top or ps command TRACEFILE_NAME command
This command prints the name of the current trace file e.g.
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)
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
ORADEBUG UNLIMIT
In Oracle 8.1.6 and above the maximum size of the trace file defaults to UNLIMITED
FLUSH command
To flush the current contents of the trace buffer to the trace file use
ORADEBUG FLUSH
CLOSE_TRACE command
To close the current trace file use
ORADEBUG CLOSE_TRACE
SUSPEND command
This command suspends the current process
First select a process using SETORAPID or SETOSPID
Do not use SETMYPID as the current ORADEBUG process will hang and cannot be resumed even from another ORADEBUG process
For example the command
ORADEBUG SUSPEND
suspends the current process
The command
ORADEBUG RESUME
resumes the current process
While the process is suspended ORADEBUG can be used to take dumps of the current process state e.g. global area, heap, subheaps etc.
This example demonstrates how to take a heap dump during a large (sorting) query
This example requires two sessions, session 1 logged on SYS AS SYSDBA and session 2 which executes the query. In session 2 identify the PID using
SELECT pid FROM v$process
WHERE addr IN
(
SELECT paddr FROM v$session
WHERE sid = dbms_support.mysid
);
In this example the PID was 12
In session 1 set the Oracle PID using
ORADEBUG SETORAPID 12
In session 2 start the query
SELECT ... FROM t1 ORDER BY ....
In session 1 suspend session 2
ORADEBUG SUSPEND
The query in session 2 will be suspended
In session 1 run the heap dump
ORADEBUG DUMP HEAPDUMP 1
The heapdump will show the memory structures allocated for the sort. At this point further dumps e.g. subheap dumps can be taken.
In session 1 resume session 2
The query in session 2 will resume execution
RESUME command
This command resumes the current process
First select a process using SETORAPID or SETOSPID
Do not use SETMYPID as the current ORADEBUG process will hang and cannot be resumed even from another ORADEBUG process
For example the command
ORADEBUG SUSPEND
suspends the current process
The command
ORADEBUG RESUME
resumes the current process
While the process is suspended ORADEBUG can be used to take dumps of the current process state e.g. global area, heap, subheaps etc.
See SUSPEND for an example of use of the SUSPEND and RESUME commands WAKEUP command
To wake up a process use
ORADEBUG WAKEUP pid
For example to wake up SMON, first obtain the PID using
SELECT pid FROM v$process
WHERE addr =
(
SELECT paddr FROM v$bgprocess
WHERE name = 'SMON'
);
If the PID is 6 then send a wakeup call using
DUMPLIST command
To list the dumps available in ORADEBUG use
ORADEBUG DUMPLIST pid
For example in Oracle 9.2 (Windows 2000) this command returns the following
DUMP command
To perform a dump use
ORADEBUG DUMP dumpname level
For example for a level 4 dump of the library cache use
ORADEBUG SETMYPID
ORADEBUG DUMP LIBRARY_CACHE 4
EVENT command
To set an event in a process use
ORADEBUG EVENT event TRACE NAME CONTEXT FOREVER, LEVEL level
For example to set event 10046, level 12 in Oracle process 8 use
ORADEBUG SETORAPID 8
ORADEBUG EVENT 10046 TRACE NAME CONTEXT FOREVER, LEVEL 12
SESSION_EVENT command
To set an event in a session use
ORADEBUG SESSION_EVENT event TRACE NAME CONTEXT FOREVER, LEVEL level
For example
ORADEBUG SESSION_EVENT 10046 TRACE NAME CONTEXT FOREVER, LEVEL 12
DUMPSGA
To dump the fixed SGA use
ORADEBUG DUMPSGA
DUMPVAR
To dump an SGA variable use
ORADEBUG DUMPVAR SGA variable_name
e.g.
ORADEBUG DUMPVAR SGA kcbnhb
which returns the number of hash buckets in the buffer cache
The names of SGA variables can be found in X$KSMFSV.KSMFSNAM. Variables in this view are suffixed with an underscore e.g.
kcbnhb_
PEEK
To peek memory locations use
ORADEBUG PEEK address length
where address can be decimal or hexadecimal and length is in bytes
For example
ORADEBUG PEEK 0x20005F0C 12
returns 12 bytes starting at location 0x20005f0c
POKE
To poke memory locations use
ORADEBUG POKE address length value
where address and value can be decimal or hexadecimal and length is in bytes
For Example
ORADEBUG POKE 0x20005F0C 4 0x46495845
ORADEBUG POKE 0x20005F10 4 0x44205349
ORADEBUG POKE 0x20005F14 2 0x5A45
WARNING Do not use the POKE command on a production system
IPC
To dump information about operating system shared memory and semaphores configuration use the command
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
Dumping the SGA
In some versions it is possible to dump the entire SGA to a file
Freeze the instance using
ORADEBUG FFBEGIN
Dump the SGA to a file using
ORADEBUG SGATOFILE directory
Unfreeze the instance using
ORADEBUG FFRESUMEINST
This works in Oracle 9.0.1 and 9.2.0 on Solaris, but fails in both versions in Windows 2000。