[MSSQL] DBCC Trace Flag 정리

Trace Flag 관련해서 잘 정리해 놓으신것 같습니다.  (시퀄 메거진을 보면 가끔씩 이분의 글들이 보이죠... )

출처 :  http://sqlserverpedia.com/wiki/Trace_Flags 

Kevin Kline

Kevin Kline

Kevin Kline is the Technical Strategy Manager for SQL Server Solutions at Quest Software, a leading provider of award winning tools for database management and application monitoring. He is a founding board member and former President of the international Professional Association for SQL Server (PASS) and frequently contributes to database technology magazines, web sites, and discussion forums. Kevin also serves the community as an adviser to SQL Saturday education program as well as a curriculum adviser for both the University of Washington and Purdue University at Calumet in their IT and Computer Science departments.

Kevin’s most popular book is SQL in a Nutshell (now in its third edition) published by O’Reilly Media. Kevin is also author or co-author on seven other IT books, including Transact-SQL Programming, Database Benchmarking: A Practical Approach, and Professional SQL Server 2008 Relational Database Design and Optimization.

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Trace flags can be used to alter SQL Server behavior temporarily. Trace flags can be turned on for a specific connection, or server-wide. Trace flags can be a great tool for troubleshooting a particular issue, however be forewarned: some trace flags are dangerous - use them at your own risk and be prepared to rebuild the server from scratch. Furthermore, functionality of certain trace flags might not be supported in future versions of SQL Server, so definitely avoid setting trace flags in your T-SQL code. We strongly recommend against using undocumented trace flags on production systems unless you're directed to do so by Microsoft's technical support. 

To turn on a particular trace flag for a given connection, you execute the DBCC TRACEON command with the trace flag number specified in parenthesis, as follows:

1./* send the output of DBCC commands to the client */  DBCC TRACEON (3604)

To enable a trace flag on the SQL Server instance level you need to start SQL Server with the /T parameter followed by the trace flag number. If you start SQL Server with a trace flag, all connections will automatically have the same trace flag turned on. For example, to collect deadlock related information you could start the default instance of the SQL Server instance from the command prompt as follows:

1.NET START MSSQLSERVER /T1205

You can check the status of a particular trace flag by executing DBCC TRACESTATUS. Turn off a previously turned on trace flag using DBCC TRACEOFF. For example:

1.DBCC TRACESTATUS(3604)  DBCC TRACEOFF(3604)

You can check all trace flags turned on for the current connection by passing -1 as the parameter of DBCC TRACESTATUS, for example:

1.DBCC TRACESTATUS(-1)

Results:

1.TraceFlag  Status   ---------  ------   2520       1  3604       1

If you have no trace flags turned on, SQL Server will return the following message:

1.Trace option(s) not enabled for this connection. Use 'DBCC TRACEON()'.

Next, we discuss some of the more frequently used trace flags. As mentioned above, some of these can be very powerful and therefore should be handled with care.

Contents [hide] 1 DBCC TRACEON / TRACEOFF (-1) 2 DBCC TRACEON (2528) 3 DBCC TRACEON(3604) and DBCC TRACEON(3605) 4 DBCC TRACEON(1204) , DBCC TRACEON(1205) and DBCC TRACEON(1206) 5 DBCC TRACEON(3205) 6 DBCC TRACEON (4013) 7 DBCC TRACEON(4022) 8 DBCC TRACEON(2520) 9 DBCC TRACEON(2588) 10 DBCC TRACEON(1200) 11 DBCC TRACEON (1807) 12 DBCC TRACEON(4030), DBCC TRACEON(4031) and DBCC TRACEON(4032) 13 DBCC TRACEON(8202)

DBCC TRACEON / TRACEOFF (-1)

This flag advises SQL Server to turn on the trace flags turned on for the current connection on all subsequent client connections. For example, if you have turned on 3604 and 2520 on the current connection and you execute DBCC TRACEON(-1) all subsequent connections to the server will have 3604 and 2520 turned on. Similarly, if you wish to turn a particular trace flag for all connections simply execute it along with -1, as in DBCC TRACEON(-1, 3604). Executing DBCC TRACEOFF(-1) will automatically turn off all trace flags on the current and any subsequent connections.

DBCC TRACEON (2528)

This flag disables parallelism during executing of maintenance DBCC statements, such as DBCC CHECKDB, DBCC CHECKFILEGROUP and DBCC CHECKTABLE. By default SQL Server will determine the needed degree of parallelism during query execution. Usually it is recommended to let SQL Server decide whether parallelism will be useful. Occasionally, if you only wish to use a single processor for DBCC statements, you might wish to override the default behavior. Remember that turning off parallelism might increase the total time required for executing DBCC commands.

DBCC TRACEON(3604) and DBCC TRACEON(3605)

The first flag (3604) sends the output of (some) DBCC commands and trace flags to the Query Analyzer; 3605 sends the same output to SQL Server error log. For example, the following commands will generate a list of the 10 longest buffer chains in Query Analyzer:

1.DBCC TRACEON(3604)  DBCC BUFCOUNT

Results:

1.**** THE 10 LONGEST BUFFER CHAINS ****       bucket number = 514     chain size = 3     bucket number = 522     chain size = 2     bucket number = 770     chain size = 2     bucket number = 1026    chain size = 2     bucket number = 269     chain size = 1     bucket number = 272     chain size = 1     bucket number = 274     chain size = 1     bucket number = 281     chain size = 1     bucket number = 283     chain size = 1     bucket number = 284     chain size = 1    The Smallest Chain Size is: 0    The Average Chain Size is: 0.005066

If you turn off 3604 and turn on 3605, instead you'll get the same result in the error log. You can double check this by executing the following:

1.EXEC master..xp_readerrorlog

Abbreviated results:

1.ERRORLOG                                                                        ContinuationRow  2003-10-24 21:00:31.51 spid51       bucket number = 514       chain size= 3    0  2003-10-24 21:00:31.51 spid51       bucket number = 522       chain size = 2    0  2003-10-24 21:00:31.51 spid51       bucket number = 770       chain size = 2    0  2003-10-24 21:00:31.51 spid51       bucket number = 1026      chain size = 2    0  2003-10-24 21:00:31.51 spid51       bucket number = 269       chain size = 1    0  2003-10-24 21:00:31.51 spid51       bucket number = 272       chain size = 1    0  2003-10-24 21:00:31.51 spid51       bucket number = 274       chain size = 1    0  2003-10-24 21:00:31.51 spid51       bucket number = 281       chain size = 1    0  2003-10-24 21:00:31.51 spid51       bucket number = 283       chain size = 1    0  2003-10-24 21:00:31.51 spid51       bucket number = 284       chain size = 1    0  2003-10-24 21:00:31.51 spid51      The Smallest Chain Size is: 0                0  2003-10-24 21:00:31.51 spid51      The Average Chain Size is: 0.005066          0

DBCC TRACEON(1204) , DBCC TRACEON(1205) and DBCC TRACEON(1206)

These trace flags are used to troubleshoot deadlocks. 1204 returns deadlock chains and the victim SPID. 1205 returns the details of the commands (stack traces) involved in the deadlock. Along with these flags you should also turn on 3605 to send the output of the trace to the SQL Server error log. 1206 can be used to supplement the information collected by the other two trace flags by returning all lock activities performed by deadlocked connections. The output of 1206 can be very large. 

If you wish to see what deadlock output looks like, simply open two connections to the same SQL Server instance through Query Analyzer and execute following on one of them:

1.DBCC TRACEON(-1, 1204)  DBCC TRACEON(-1, 1205)  DBCC TRACEON(-1, 3605)

Next execute the following on the first connection:

1.USE pubs  BEGIN TRAN  UPDATE titles   SET title = 'deadlock battle'    WAITFOR DELAY'00:00:05'    UPDATE authors   SET address = '110 north main'

At the same time execute the following script from the other connection:

1.USE pubs  BEGIN TRANSACTION  UPDATE authors   SET address = '115 East 43rd street'   UPDATE titles   SET title = 'who can win?'

One of these connections will be chosen as a deadlock victim and its transaction will be aborted by SQL Server. Now if you read the error log, you will find entries similar to the following:

1.spid4     ----------------------------------      spid4     Starting deadlock search 1     spid4     Target Resource Owner:       spid4      ResType:LockOwner Stype:'OR' Mode: U SPID:53 ECID:  Ec:( x195 756 )               Value: x1916eb4     spid4      Node:1  ResType:LockOwner Stype:'OR' Mode: U SPID:53 ECID:  Ec:( x195 756 )               Value: x1916eb4     spid4     spid4     End deadlock search 1 ... a deadlock was not found.      spid4     ----------------------------------      spid4    ----------------------------------    spid4     Starting deadlock search 2      spid4     Target Resource Owner:      spid4      ResType:LockOwner Stype:'OR' Mode: U SPID:52 ECID:  Ec:( x1947756 )                Value: x1916e72     spid4      Node:1  ResType:LockOwner Stype:'OR' Mode: U SPID:52 ECID:  Ec:( x1947756 )                Value: x1916e72     spid4      Node:2  ResType:LockOwner Stype:'OR' Mode: U SPID:53 ECID:  Ec:(x195 756 )                Value: x1916eb4     spid4      Cycle:  ResType:LockOwner Stype:'OR' Mode: U SPID:52 ECID:  Ec:( x1947756 )                Value: x1916e72      spid4       spid4       spid4     <b>Deadlock cycle was encountered .... verifyingcycle</b>     spid4      Node:1  ResType:LockOwner Stype:'OR' Mode: U SPID:52 ECID:  Ec:(x1947756 )                Value: x1916e72  Cost:( /16  )    spid4      Node:2  ResType:LockOwner Stype:'OR' Mode: U SPID:53 ECID:  Ec:( x195 756 )                Value: x1916eb4  Cost:( /B88)     spid4      Cycle:  ResType:LockOwner Stype:'OR' Mode: U SPID:52 ECID:  Ec:( x1947756 )                Value: x1916e72  Cost:( /16  )    spid4     spid4   <b>Deadlock encountered .... Printing deadlock information</b>     spid4     spid4     Wait-for graph     spid4     spid4     Node:1    spid4     KEY: 5:1977 58 79:1 ( 1 1aedb232b) CleanCnt:1 Mode: X Flags:  x    spid4      Grant List::    spid4        Owner: x1916ee2  Mode: X        Flg: x  Ref:  Life: 2       SPID:53 ECID:    spid4        SPID: 53 ECID:   Statement Type: UPDATE Line #: 1    spid4        Input Buf:Language Event: <b>begin tran   update authors set address = '115 East 43rd street '  update titles set title = 'who can win?'</b>     spid4      Requested By:     spid4        ResType:LockOwner Stype:'OR' Mode: U SPID:52 ECID:  Ec:( x1947756)                  Value: x1916e72  Cost:( /16  )    spid4       spid4     Node:2     spid4     KEY: 5:2121 58592:1 (a7  64fb1eac) CleanCnt:1 Mode: X Flags:  x     spid4     Grant List::     spid4        Owner: x191813   Mode: X        Flg: x  Ref:  Life: 2       SPID:52 ECID:    spid4        SPID: 52 ECID:   Statement Type: UPDATE Line #: 1    spid4        Input Buf: Language Event: <b>begin tran   update titles set title=' deadlock battle''    waitfor delay '  :  : 5'  update authors set address='110 north main'</b>     spid4      Requested By:     spid4        ResType:LockOwner Stype:'OR' Mode: U SPID:53 ECID:  Ec:( x195 756 )                  Value: x1916eb4  Cost:( /B88)    spid4     Victim Resource Owner:     spid4      ResType:LockOwner Stype:'OR' Mode: U SPID:53 ECID:  Ec:( x195 756 )                Value: x1916eb4  Cost:( /B88)    spid4     spid4     <b>End deadlock search 2 ... a deadlock was found.</b>     spid4     ----------------------------------     spid4     ----------------------------------     spid4     Starting deadlock search 3    spid4     Target Resource Owner:     spid4      ResType:LockOwner Stype:'OR' Mode: U SPID:53 ECID:  Ec:( x195 756 )                Value: x1916eb4     spid4      Node:1  ResType:LockOwner Stype:'OR' Mode: U SPID:53 ECID:  Ec:( x195 756 )                Value: x1916eb4     spid4      Node:2  ResType:LockOwner Stype:'OR' Mode: U SPID:52 ECID:  Ec:( x1947756 )                Value: x1916e72     spid4     spid4     <b>Previous victim encountered ... aborting search</b>          spid4     spid4     End deadlock search 3 ... a deadlock was not found.        spid4    ----------------------------------

If you had also turned on trace flag 1206 you would get numerous messages similar to the following in the error log:

1.Process 52 acquiring IX lock on PAG: 5:1:99 (class bit2000000 ref1)   result: OK  Process 52 acquiring X lock on KEY: 5:2121058592:1 (b60057ff7752) (class bit2000000 ref1)  result: OK  Process 52 releasing lock reference on KEY: 5:2121058592:2 (9002e988d824) Process 5 releasing all locks @19116B3C

DBCC TRACEON(3205)

This flag disables hardware compression for tape drives. If the tape drive supports the compression, the BACKUP statement that backs up the database directly to tape will take advantage of hardware compression. If you must exchange tapes with another office where hardware compression is not supported, you might wish to turn on trace flag 3205 so that your tapes are compatible with the other office's hardware.

DBCC TRACEON (4013)

This flag can be used to audit connections to the server. When turned on, the SQL Server error log will contain an entry for each successful connection. The log entry will look similar to the following:

1.Login: johndoe BP-5CHSFFH2HEJ1johndoejohndoeSQL Query AnalyzerBP-5CHSFFH2HEJ1ODBCmaster,   server process ID (SPID): 55, kernel process ID (KPID): 55.

As you might imagine the error log on a busy server will grow quite voluminous if this flag is turned on.

DBCC TRACEON(4022)

This flag is used to bypass procedures marked for automatic execution at startup. Note that automatically executed procedures are also skipped if SQL Server is started with minimal configuration.

DBCC TRACEON(2520)

This flag can be used to force DBCC HELP to return syntax of undocumented DBCC statements. If 2520 is not turned on, DBCC HELP will refuse to give you the syntax stating: "No help available for DBCC statement 'undocumented statement'".

DBCC TRACEON(2588)

This flag can be used to force DBCC HELP to return syntax of undocumented DBCC statements in SQL Server 2005 and 2008.

1.DBCC TRACEON (2588);DBCC HELP ('?') GO DBCC TRACEOFF (2588);

DBCC TRACEON(1200)

This flag can be used to get a detailed report of all locks acquired by each SQL statement on the current connection - the output can be large depending on the number of rows involved. For example, take a look at the output of the following simple query:

1.SELECT a.au_id, b.royaltyper  FROM authors a INNER JOIN titleauthor b  ON a.au_id =b.au_id  ORDER BY 2

Results (abbreviated):

1.Process 54 acquiring IS lock on TAB: 5:53575229 [] (class bit0 ref1) result: OK  Process 54 acquiring IS lock on TAB: 5:1977058079 [] (class bit0 ref1) result: OK  Process 54 acquiring IS lock on PAG: 5:1:148 (class bit0 ref1) result: OK  Process 54 acquiring ISlock on PAG: 5:1:102 (class bit0 ref1) result: OK  Process 54 releasing lock on PAG: 5:1:102  Process 54 acquiring IS lock on PAG: 5:1:102 (class bit0 ref1) result: OK  Process 54 releasing lock on PAG: 5:1:102  Process 54 acquiring IS lock on PAG: 5:1:102(class bit0 ref1) result: OK  Process 54 releasing lock on PAG: 5:1:102  Process 54 acquiring IS lock on PAG: 5:1:102 (class bit0 ref1) result: OK  Process 54 releasing lockon PAG: 5:1:102  Process 54 acquiring IS lock on PAG: 5:1:102 (class bit0 ref1) result: OK  Process 54 releasing lock on PAG: 5:1:102  Process 54 acquiring IS lock on PAG: 5:1:102 (class bit0 ref1) result: OK  Process 54 releasing lock on PAG: 5:1:102  Process 54 acquiring IS lock on PAG: 5:1:102 (class bit0 ref1) result: OK  Process 54 releasing lock on PAG: 5:1:102  Process 54 acquiring IS lock on PAG: 5:1:102 (class bit0 ref1)result: OK  Process 54 releasing lock on PAG: 5:1:102  Process 54 acquiring IS lock onPAG: 5:1:102 (class bit0 ref1) result: OK  Process 54 releasing lock on PAG: 5:1:102  …

DBCC TRACEON (1807)

This flag can be used to allow the creation of database files on a network share. You must specify a valid UNC path to the share in order to create database and log files.

1.DBCC TRACEON(3607), DBCC TRACEON(3608) and DBCC TRACEON(3609)

These flags can be used to skip the recovery process during SQL Server startup. 3607 does not recover any databases, 3608 recovers the master only. In addition, both trace flags cause SQL Server to skip stored procedures marked for automatic execution. Trace flag 3609 skips creation and clearing of tempdb at startup. Warning: do NOT use trace flags 3607-3609 unless you are directed to do so by Microsoft support professional.

DBCC TRACEON(4030), DBCC TRACEON(4031) and DBCC TRACEON(4032)

Flags 4030 and 4031 can be used to write the SQL statements submitted and output returned to the connections. Their functionality is similar to DBCC INPUTBUFFER and DBCC OUTPUTBUFFER respectively. The difference is that trace flags record all information in the error log for all connections. For example, we can set both of these flags globally and send the output to the error log with the following:

1.DBCC TRACEON(-1, 4031)  DBCC TRACEON(-1, 4030)  DBCC TRACEON(-1, 3605)

Next, execute a simple statement such as:

1.SELECT TOP 1 * FROM authors

You will see entries similar to the following in the error log:

1.2003-10-24 23:09:08. spid52     Printing receive buffer:  01 01 00 42 00 00 01 00 53 00 45 00 4C 00 45 00   ...B....S.E.L.E.  43 00 54 00 20 00 54 00 4F 00 50 00 20 00 31 00   C.T. .T.O.P. .1.  20 00 2A 00 20 00 46 00 52 00 4F 00 4D 00 20 00    .*. .F.R.O.M. .    2003-10-24 23:09:08.78 spid52    61 00 75 00 74 00 68 00 6F 00 72 00 73 00 0D 00   a.u.t.h.o.r.s...      2003-10-24 23:09:08. spid52     Printing send buffer:     04 01 01 41 00 34 01 00 81 09 00 01 01 08 00 A7   ...A.4..........  0B 00 09 04 D0 00 34 05 61 00 75 00 5F 00 69 00   ......4.a.u._.i.  64 00 00 00 08 00 A7 28 00 09 04 D0 00 34 08 61   d......(.....4.a  00 75 00 5F 00 6C 00 6E 00 61 00 6D 00 65 00 00   .u._.l.n.a.m.e..  00 08 00 A7 14 00 09 04 D0 00 34 08 61 00 75 00   ..........4.a.u.  5F 00 66 00 6E 00 61 00 6D 00 65 00 00 00 08 00   _.f.n.a.m.e.....  AF 0C 00 09 04 D0 00 34 05 70 00 68 00 6F 00 6E   .......4.p.h.o.n  00 65 00 00 00 09 00 A7 28 00 09 04 D0 00 34 07   .e......(.....4.

Flag 4032 can be used to record every SQL statement executed against the server in the error log. The log entries will look similar to the following:

1.Text:use [pubs]  ODS Event: Language Exec  Text:SELECT TOP 1 * FROM authors

DBCC TRACEON(8202)

Used for replication, this flag forces SQL Server to replicate UPDATE statements as DELETE followed by an INSERT. This behavior could be useful if you wish to perform custom processing in replication stored procedures. For instance, you could write a record to the audit table every time record is updated through replication.