All About Tracing Oracle SQL Sessions

HOW TO trace your own session Platform: DB Ver: Revision Date: Goal To trace the Facts Solution

Oracle App: 9.2 App Ver: 28-Nov-2005 Keywords: HOWTO, TRACE, SESSION SQL in your own session

First, run the following commands from the SQL*Plus command prompt to switch on timed statistics and to allow for an unlimited trace file size. alter session set timed_statistics=true alter session set max_dump_file_size=unlimited If you fail to set TIMED_STATISTICS=TRUE, your database kernel will emit only zero values instead of real durations into your trace file. If your setting of MAX_DUMP_FILE_SIZE is too restrictive, you'll suffer the chagrin of generating a message like the following in your trace file instead of the timing data you wanted: *** DUMP FILE SIZE IS LIMITED TO 1048576 BYTES *** Before starting your trace, you can modify the name of the trace file by adding a TRACEFILE_IDENTIFIER to it. You can do this by an ALTER SESSION command such as what is below. alter session set TRACEFILE_IDENTIFIER = 'something_unique'; Next comes activating the trace itself. There are several ways to do this. The oldfashioned way is to use the ALTER SESSION command as follows: alter session set events '10046 trace name context forever, level 12' /* code to be traced goes here */ alter session set events '10046 trace name context off' A more elegant way to accomplish the extended SQL trace activation is to use the DBMS_SUPPORT package: dbms_support.start_trace(waits=>true, binds=>true) /* code to be traced goes here */ dbms_support.stop_trace() To find the trace file, first find the directory where it is located using the following: select value from v$parameter where name = 'user_dump_dest';

Then, look for a file with 'something_unique' in the filename.

HOW TO trace a 3rd party session

Platform: Oracle App: DB Ver: 9.2 App Ver: Revision 26-Oct-2006 Keywords: HOWTO, TRACE, SESSION, 3RD PARTY Date: Goal To trace the SQL in 3rd party session Facts Solution First, identify the 3rd party session to be traced. This can be cumbersome, but can be identified usi session has been identified make a note of the session's: SID Serial# Next, run the following commands from the SQL*Plus command prompt to switch on timed statistics and to allow for an unlimited trace file size. alter session set timed_statistics=true alter session set max_dump_file_size=unlimited If you fail to set TIMED_STATISTICS=TRUE, your database kernel will emit only zero values instead of real durations into your trace file. If your setting of MAX_DUMP_FILE_SIZE is too restrictive, you'll suffer the chagrin of generating a message like the following in your trace file instead of the timing data you wanted: *** DUMP FILE SIZE IS LIMITED TO 1048576 BYTES *** Before starting your trace, you can modify the name of the trace file by adding a TRACEFILE_IDENTIFIER to it. You can do this by an ALTER SESSION command such as what is below. alter session set TRACEFILE_IDENTIFIER = 'something_unique'; Next comes activating the trace itself. There are several ways to do this. The old-fashioned way is to use the ALTER SESSION command as follows: A more elegant way to accomplish the extended SQL trace activation is to use the DBMS_SYSTEM package: DBMS_System.Set_Ev(sid, serial#, event, level, name); e.g. DBMS_System.Set_Ev(31, 97, 10046, 4,); To find the trace file, first find the directory where it is located using the following:

select value from v$parameter where name = 'user_dump_dest'; Then, look for a file with 'something_unique' in the filename.

Structure of an Extended SQL Trace file Platform: Oracle App: DB Ver: 9.2 App Ver: Revision 30-DecKeywords: REF, REFERENCE, TRACE FILE STRUCTURE Date: 2005 Reference For any updates, refer to the original Metalink document Metalink:39817.1. Introduction. between any 2 operations This is a short reference article which summarises the output format of the raw SQL_TRACE output file. The second part of the article describes the additional trace lines that may be enabled by the DBMS_SUPPORT package. See Metalink Note 62294.1 for details of this package. Note: The format may vary slightly between releases. APPNAME mod='%s' mh=%lu act='%s' ah=%lu APPNAME Application name setting. (This only applies to Oracle 7.2 and above. This can be set by using the DBMS_APPLICATION_INFO package. See Note 30366.1.) mod Module name. mh Module hash value. act Action. ah Action hash value. PARSING IN CURSOR # len=X dep=X uid=X oct=X lid=X tim=X hv=X ad='X' END OF STMT Cursor number. len Length of SQL statement. dep Recursive depth of the cursor. uid Schema user id of parsing user. oct Oracle command type. lid Privilege user id. tim Timestamp. Pre-Oracle9i, the times recorded by Oracle only have a resolution of 1/100th of a second (10mS). As of Oracle9i some times are available to microsecond accuracy (1/1,000,000th of a second). The timestamp can be used to determine times between points the trace file. The value is the value in V$TIMER when the line was written. If there are TIMESTAMPS in the file you can use the difference between 'tim' values to determine an absolute time. hv Hash id. ad SQLTEXT address (see and ). The actual SQL statement being parsed. PARSE ERROR #%d:len=%ld dep=%d uid=%ld oct=%d lid=%ld tim=%lu err=%d ...

PARSE ERROR In Oracle 7.2+ parse errors are reported to the trace file. len Length of SQL statement. dep Recursive depth of the statement uid User id. oct Oracle command type (if known). lid Privilege user id. tim Timestamp. err Oracle error code (e.g. ORA-XXXXX) reported The SQL statement that errored. If this contains a password, the statement is truncated as indicated by '...' at the end. PARSE #:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=0 EXEC #:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=0 FETCH #:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=0 UNMAP #:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=0 - OPERATIONS: PARSE Parse a statement. EXEC Execute a pre-parsed statement. FETCH Fetch rows from a cursor. UNMAP If the cursor uses a temporary table, when the cursor is closed you see an UNMAP when we free up the temporary table locks.(Ie: free the lock, delete the state object, free the temp segment) In tkprof, UNMAP stats get added to the EXECUTE statistics. SORT UNMAP As above, but for OS file sorts or TEMP table segments. c CPU time (100th's of a second in Oracle7 ,8 and 9). e Elapsed time (100th's of a second Oracle7, 8 and 1,000,000ths (Microseconds) in Oracle 9 onwards). p Number of physical reads. cr Number of buffers retrieved for CR reads. cu Number of buffers retrieved in current mode. mis Cursor missed in the cache. r Number of rows processed. dep Recursive call depth (0 = user SQL, >0 = recursive). og Optimizer goal: 1=All_Rows, 2=First_Rows, 3=Rule, 4=Choose tim Timestamp (large number in 100ths of a second). Use this to determine the time ERROR #%d:err=%d tim=%lu SQL Error shown after an execution or fetch error. err Oracle error code (e.g. ORA-XXXXX) at the top of the stack. tim Timestamp. STAT # id=N cnt=0 [pid=0 pos=0 obj=0 op='SORT AGGREGATE '] STAT Lines report explain plan statistics for the numbered . Cursor which the statistics apply to. id Line of the explain plan which the row count applies to (starts at line 1). This is effectively the row source row

count for all row sources in the execution tree. cnt Number of rows for this row source. As of 7.3.3 the items in '[...]' are also reported: pid Parent id of this row source. pos Position in explain plan. obj Object id of row source (if this is a base object). op='...' The row source access operation. These let you know the 'run time' explain plan. XCTEND rlbk=%d rd_only=%d XCTEND A transaction end marker. rlbk 1 if a rollback was performed, 0 if no rollback (commit). rd_only 1 if transaction was read only, 0 if changes occurred. ========================================================== The items below are only output if WAITS or BINDS are being traced. These can be enabled with the DBMS_SUPPORT package. ========================================================== BINDS #%d: bind 0: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=0 size=24 offset=0 bfp=02fedb44 bln=22 avl=00 flg=05 value=10

BIND Variables bound to a cursor. bindN dty mxl mal scl pre oacflg oacflg2 size offset bfp bln avl flg value

The bind position being bound. Data type (see ). Maximum length of the bind variable (private max len in paren). Array length. Scale. Precision. Special flag indicating bind options Continuation of oacflg Amount of memory to be allocated for this chunk Offset into this chunk for this bind buffer Bind address. Bind buffer length. Actual value length (array length too). Special flag indicating bind status The actual value of the bind variable. Numbers show the numeric value, strings show the string etc...

WAIT #: nam="" ela=0 p1=0 p2=0 p3=0

WAIT

An event that we waited for.

nam

What was being waited for . The wait events here are the same as are seen in . For any Oracle release a full list of wait events and the values in P1, P2 and P3 below can be seen in

ela p1 p2 p3

Elapsed time for p1 for the given p2 for the given p3 for the given

the operation wait event wait event wait event

Example (Full Table Scan): WAIT #1: nam="db file scattered read" ela= 5 p1=4 p2=1435 p3=25 WAITing under CURSOR no 1 for "db file scattered read" We waited 0.05 seconds For a read of: File 4, start block 1435, for 25 Oracle blocks Example (Index Scan): WAIT #1: nam="db file sequential read" ela= 4 p1=4 p2=1224 p3=1 WAITing under CURSOR no 1 for "db file sequential read" We waited 0.04 seconds for a single block read (p3=1) from file 4, block 1224.

HOW TO find SQL trace file directories Platform: Oracle DB Ver: 9.2 Revision Date: 17-Sep-2005

App: App Ver: Keyword HOWTO, TRACE FILES, DIRECTORIES, DIRECTORY s:

Goal To find directories on the database server where SQL trace files are located Facts Solution

Run the SQL script: SELECT name, value FROM v$parameter2 WHERE name IN ('user_dump_dest' ,'background_dump_dest' ,'core_dump_dest')

HOW TO find a user's session info for tracing Platform:

Oracle

App:

DB Ver: 9.2 App Ver: Revision 12-Sep-2005 Keywords: HOWTO, TRACING, TRACE, SESSION Date: Goal To find a user's session info (ready for tracing) Facts Solution

The following SQL script will find the SID and SERIAL# required to activate a session specific SQL trace, together with supporting information about that session. SELECT s.sid db_sid ,s.serial# db_serial ,p.spid os_pid ,to_char(s.logon_time, 'YYYY/MM/DD HH24:MI:SS') db_logon_time ,nvl(s.username, 'SYS') db_user ,s.osuser os_user ,s.machine os_machine ,nvl(decode(instr(s.terminal, chr(0)) ,0 ,s.terminal ,substr(s.terminal, 1, instr(s.terminal, chr(0))-1)),'none') os_terminal ,s.program os_program from v$session s ,v$process p where 1=1 and s.paddr = p.addr and s.username like upper('&1') /

HOW TO find a concurrent program's trace file Platform: DB Ver: Revision Date:

Oracle 9.2 28-Jun-2006

App: App Ver: Keyword HOWTO, TRACE, CONCURRENT PROGRAM s:

Goal To find the SQL trace file for a concurrent program Facts Solution Run the following script: prompt

ACCEPT request prompt 'Please enter the concurrent request id for the appropriate concurrent program:' prompt COLUMN traceid format a8 COLUMN tracename format a80 COLUMN user_concurrent_program_name format a40 COLUMN execname format a15 COLUMN enable_trace format a12 SET lines 80 SET pages 22 SET head OFF SELECT req.request_id ,req.logfile_node_name node ,req.oracle_Process_id ,req.enable_trace ,dest.VALUE||'/'||LOWER(dbnm.VALUE)||'_ora_'|| oracle_process_id||'.trc' trace_filename ,prog.user_concurrent_program_name ,execname.execution_file_name ,execname.subroutine_name ,phase_code ,status_code ,ses.SID ,ses.serial# ,ses.module

,ses.machine FROM fnd_concurrent_requests req ,v$session ses ,v$process proc ,v$parameter dest ,v$parameter dbnm ,fnd_concurrent_programs_vl prog ,fnd_executables execname WHERE 1=1 AND req.request_id = &request AND req.oracle_process_id=proc.spid(+) AND proc.addr = ses.paddr(+) AND dest.NAME='user_dump_dest' AND dbnm.NAME='db_name' AND req.concurrent_program_id = prog.concurrent_program_id AND req.program_application_id = prog.application_id AND prog.application_id = execname.application_id AND prog.executable_id=execname.executable_id

HOW TO trace SQL*Plus client Platform: Oracle App: DB Ver: 9.2 App Ver: Revision 19-Oct-2005 Keywords: HOWTO, TRACE, SQL*PLUS Date: Goal Switch tracing on for the SQL*Plus client application Facts Solution To set up the trace on client: Include the following parameters in SQLNET.ORA file located in $ORACLE_HOME/network/admin: trace_level_client = 16 trace_file_client = cli.trc trace_directory_client = c:\tmp trace_unique_client = on trace_timestamp_client = on trace_filelen_client = 100 trace_fileno_client = 2 log_file_client = cli log_directory_client = c:\tmp tnsping.trace_directory = c:\tmp tnsping.trace_level = admin