Interpreting Raw SQL_TRACE output (文档 ID 39817.1)

译文：了解raw trace文件的各项内容

APPLIES TO:

Oracle Server - Standard Edition - Version 8.0.3.0 and later
Oracle Server - Personal Edition - Version 8.0.3.0 and later
Oracle Server - Enterprise Edition - Version 8.0.3.0 and later
Information in this document applies to any platform.

PURPOSE

This is a short reference article which summarises the output format of the raw SQL_TRACE output file. 

Note: The format may vary slightly between releases.

SCOPE

Persons wishing to interpret raw SQL_TRACE output. Expertise level is high.

DETAILS

Note:  Square brackets :  ( [ and ] )  are used to enclose some sections where specific text has been removed. These are not in the original text and are included for visibility. So, for example :

WAIT #1: nam="event name" ela=0 p1=0 p2=0 p3=0

in the trace would be shown as :

WAIT #[CURSOR]: nam="event name" ela=0 p1=0 p2=0 p3=0

in this document with [CURSOR] replacing the cursor number.

 

Standard Output

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 #[CURSOR] len=X dep=X uid=X oct=X lid=X tim=X hv=X ad='X'
[statement]
END OF STMT

    [CURSOR]	Cursor number.

    len		Length of SQL statement.
    dep		Recursive depth of the cursor.
    uid		Schema id under which SQL was parsed.
    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 
                in the trace file.
		The value is the value in V$TIMER when the line was written.
                The timer has platform-specific implementation differences.
		If there are TIMESTAMPS in the file you can use the difference
		between 'tim' values to determine an absolute time.
    hv		Hash id. 
    ad		SQLTEXT address (see views V$SQLAREA Note:43761.1 and V$SQLTEXT Note:43764.1).

    [statement]	The actual SQL statement being parsed.

PARSE ERROR #%d:len=%ld dep=%d uid=%ld oct=%d lid=%ld tim=%lu err=%d
[statement] ...

    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
        
    [statement]	The SQL statement that errored.  If this contains a password,
		the statement is truncated as indicated by '...' at the end.

PARSE #[CURSOR]:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=0 
EXEC #[CURSOR]:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=0
FETCH #[CURSOR]:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=0
UNMAP #[CURSOR]: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 (centiseconds prior to 9i, microseconds rounded to 
                centiseconds granularity on 9i and above)
	e	Elapsed time (centiseconds prior to 9i, microseconds thereafter)
	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 (100th's of sec < Oracle9i, Microseconds thereafter)
                Use this to determine the time between any 2 operations.

CLOSE #[CURSOR]:c=%u e=%u dep=%d type=%u tim=%u

  
    CLOSE       cursor is closed
    c           CPU time (centiseconds prior to 9i, microseconds rounded to 
                centiseconds granularity on 9i and above)
    e           Elapsed time (centiseconds prior to 9i, microseconds thereafter)
    dep		Recursive depth of the cursor
    type        type of close operation

	tim	Timestamp (100th's of sec < Oracle9i, Microseconds thereafter)
                Use this to determine the time between any 2 operations.

ERROR #%d:err=%d tim=%lu

    ERROR       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 #[CURSOR] id=N cnt=0 [pid=0 pos=0 obj=0 op='SORT AGGREGATE ']

    STAT        Lines report explain plan statistics for the numbered [CURSOR].

    [CURSOR]	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.

    11g and above:

    In 11g the "op=" section has been expanded so that STAT lines contain more information. For example:

STAT #[CURSOR] id=1 cnt=1 pid=0 pos=1 obj=0 
        op='SORT AGGREGATE (cr=6 pr=0 pw=0 time=483 us)'
STAT #[CURSOR] id=2 cnt=14 pid=1 pos=1 obj=75510 
        op='TABLE ACCESS FULL EMP (cr=6 pr=0 pw=0 time=432 us cost=2 size=0 card=14)'

    cr 		Consistent reads.
    pr 		Physical reads.
    pw		Physical writes.
    time      	Elapsed time taken by the operation (in microseconds).
    cost		Optimizer cost of the operation.
    size		Estimated size (in bytes).
    card		Estimated Optimizer Cardinality.

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.
  

RPC Remote Procedure Calls

    These are logged and interpreted in a similar manner, here is an example:

RPC CALL:FUNCTION APPS.ARP_TAX_VENDOR.IS_GEOCODE_VALID(P_GEOCODE IN VARCHAR2) RETURN BOOLEAN;
RPC BINDS:
bind 0: dty=1 bfp=60000000005e4db8 flg=08 avl=09 mxl=30 val="161630280"
bind 1: dty=3 bfp=60000000005e4df8 flg=02 avl=04 mxl=04 val=00
RPC EXEC:c=0,e=162

Additional Wait/Bind Tracing Output

The items below are only output if WAITS or BINDS are being traced.
Following notes explain how to get a sql trace file with WAIT and/or BIND information.  

Document 376442.1 How To Collect 10046 Trace (SQL_TRACE) Diagnostics for Performance Issues
Document 21154.1 EVENT: 10046 "enable SQL statement tracing (including binds/waits)"

BINDS #[BIND]:
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.  

    bind N	The bind position being bound.
    dty		Data type

    mxl		Maximum length of the bind variable (private max len in paren).
    mal		Array length.
    scl		Scale.
    pre		Precision.
    oacflg	Special flag indicating bind options

    oacflg2     Continuation of oacflg

    size        Amount of memory to be allocated for this chunk
    offset      Offset into this chunk for this bind buffer

    bfp         Bind address.
    bln	        Bind buffer length. 
    avl	        Actual value length (array length too).
    flg	        Special flag indicating bind status

value	The actual value of the bind variable.  
		Numbers show the numeric value, strings show the string etc...

If a message such as : "bind 6: (No oacdef for this bind)" is seen then this means that there is no bind data defined at the time of the dump. This can mean that the cursor is being dumped before the cursor has been bound, for example. It is also possible to see "bind 6: (No oacdef for this bind)", if no separate bind buffer exists for some other reason.

WAIT #[CURSOR]: nam="event name" 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 
		view V$SESSION_WAIT Note:43718.1. For any Oracle release a 
                full list of wait events and the values in P1, P2 and P3 below
                can be seen in view V$EVENT_NAME Note:43721.1
    ela 	Elapsed time for the operation.
    p1		P1 for the given wait event. 
    p2		P2 for the given wait event.
    p3		P3 for the given wait event.

Note: Starting with 11g, Traces have started to replace P1, P2 and P3 
with more meaningful phrases related to the actual event in question

11g WAIT Examples

(Index Scan) from Oracle11g (elapsed time in microseconds):

WAIT #6: nam='db file sequential read' ela= 8458 file#=110 block#=63682 blocks=1 obj#=221 tim=506028963546

Explanation: Completed WAITing under CURSOR no 6 for "db file sequential read" We waited 8458 microseconds i.e. approx. 8.5 milliseconds For a read of: File 110, start block 63682, for 1 Oracle block of Object number 221. Timestamp was 506028963546

WAIT #1: nam='library cache: mutex X' ela= 814 idn=3606132107 value=3302829850624 where=4 obj#=-1 tim=995364327604

Explanation: Completed WAITing under CURSOR no 1 for "library cache: mutex X" We waited 814 microseconds i.e. approx. 0.8 milliseconds To get an eXclusive library cache latch with Identifier 3606132107 value 3302829850624 location 4 It was not associated with any particular object (obj#=-1) Timestamp 995364327604

9i WAIT Example

(Full Table Scan) from Oracle9i (elapsed time in microseconds):

WAIT #1: nam="db file scattered read" ela=5010 p1=4 p2=1435 p3=25

Explanation: Completed WAITing under CURSOR no 1 for "db file scattered read". We waited 5010 microseconds i.e. approx. 5 milliseconds for a read of: File 4, start block 1435, for 25 Oracle blocks

8i WAIT Example

(Index Scan) from Oracle8i (elapsed time in centiseconds):

WAIT #1: nam="db file sequential read" ela=4 p1=4 p2=1224 p3=1

Explanation: Completed 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

Note: WAIT lines in trace refer to completed waits. The current WAIT cannot be 
seen in the standard SQL_TRACE trace output. A trace providing a PROCESS STATE 
or similar is required to see the current wait.

REFERENCES

NOTE:21154.1 - EVENT: 10046 "enable SQL statement tracing (including binds/waits)"
NOTE:30366.1 - PACKAGE DBMS_APPLICATION_INFO Specification
NOTE:376442.1 - * How To Collect 10046 Trace (SQL_TRACE) Diagnostics for Performance Issues
NOTE:43718.1 - VIEW: "V$SESSION_WAIT" Reference Note
NOTE:43721.1 - VIEW: "V$EVENT_NAME" Reference Note
NOTE:43761.1 - VIEW: "V$SQLAREA" Reference Note
NOTE:43764.1 - VIEW: "V$SQLTEXT" Reference Note
@ NOTE:94160.1 - Summary of Oracle DATATYPES

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• Oracle Database Products > Oracle Database > Oracle Database > Oracle Database - Personal Edition > RDBMS > Database Level Performance Issues (not SQL Tuning)
• Oracle Database Products > Oracle Database > Oracle Database > Oracle Database - Enterprise Edition > RDBMS > Database Level Performance Issues (not SQL Tuning)

关键字

SQL_TRACE; TRACE

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