FIX: Improved CPU Usage for Database Logging When Transaction Log Stalls Occur (813645)



The information in this article applies to:

  • Microsoft SQL Server 2000 (all editions) SP2

BUG #: 363963 (SHILOH_BUGS)

SYMPTOMS

SQL Server may experience unexpected CPU usage when transaction log stalls occur. This can be the result of poor log file performance or database backups in progress.

RESOLUTION

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next SQL Server 2000 Service Pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version         Size             File name
   --------------------------------------------------------------------------
   24-Jan-2003  18:53  2000.80.732.0      29,244 bytes  Dbmslpcn.dll     
   18-Jan-2003  02:23                    786,432 bytes  Distmdl.ldf
   18-Jan-2003  02:23                  2,359,296 bytes  Distmdl.mdf
   11-Dec-2002  17:50                        180 bytes  Drop_repl_hotfix.sql
   02-Jul-2002  15:35  2000.80.650.0     107,088 bytes  Impprov.dll      
   17-Jan-2003  20:33                    774,409 bytes  Instdist.sql
   11-Dec-2002  17:50                      1,402 bytes  Inst_repl_hotfix.sql
   20-Aug-2002  16:24  2000.80.679.0     111,172 bytes  Logread.exe      
   15-Dec-2002  23:21  2000.80.717.0      90,692 bytes  Msgprox.dll      
   05-Mar-2003  18:17  2000.80.736.0      62,024 bytes  Odsole70.dll     
   03-Jan-2002  01:59                     18,185 bytes  Qfe356326.sql
   20-Aug-2002  16:47  2000.80.679.0     135,748 bytes  Qrdrsvc.exe      
   26-Aug-2002  22:49  2000.80.679.0     406,088 bytes  Rdistcom.dll     
   04-Oct-2001  01:36                    437,302 bytes  Replcom.sql
   20-Aug-2002  16:33  2000.80.679.0     152,136 bytes  Replmerg.exe     
   25-Nov-2002  21:43                  1,004,990 bytes  Replmerg.sql
   15-Dec-2002  23:21  2000.80.717.0     221,768 bytes  Replprov.dll     
   15-Dec-2002  23:21  2000.80.717.0     303,688 bytes  Replrec.dll      
   22-Jan-2003  19:27                  1,002,101 bytes  Replsys.sql
   04-Oct-2001  01:36                    881,228 bytes  Repltran.sql
   26-Aug-2002  22:49  2000.80.679.0     283,208 bytes  Rinitcom.dll     
   16-Sep-2002  22:31                    390,045 bytes  Securityhotfix.sql
   26-Aug-2002  22:49  2000.80.679.0      28,672 bytes  Sqlagent.dll     
   26-Aug-2002  18:39  2000.80.679.0     311,872 bytes  Sqlagent.exe     
   28-Aug-2002  16:32  2000.80.679.0      49,152 bytes  Sqlagent.rll
   26-Aug-2002  22:49  2000.80.679.0      53,824 bytes  Sqlcmdss.dll     
   28-Aug-2002  16:40  2000.80.679.0      12,288 bytes  Sqlcmdss.rll
   14-Jan-2003  21:39  2000.80.725.0     172,600 bytes  Sqlmap70.dll     
   02-May-2003  18:44  2000.80.743.0   7,483,473 bytes  Sqlservr.exe     
   01-Nov-2002  18:56  2000.80.698.0      45,644 bytes  Sqlvdi.dll       
   24-Jan-2003  18:53  2000.80.732.0      29,244 bytes  Ssmslpcn.dll     
   24-Jan-2003  18:53  2000.80.732.0      82,492 bytes  Ssnetlib.dll     
   02-Jan-2003  20:12  2000.80.722.0      25,148 bytes  Ssnmpn70.dll     
   02-May-2003  18:44  2000.80.743.0      49,228 bytes  Ums.dll          
   07-Apr-2002  02:08  2000.80.606.0      70,208 bytes  Xplog70.dll      
   07-Apr-2002  02:08  2000.80.606.0      53,828 bytes  Xpqueue.dll      
   07-Apr-2002  02:08  2000.80.606.0     156,228 bytes  Xprepl.dll       
   12-Jul-2002  01:00  2000.80.658.0     279,104 bytes  Xpstar.dll       
   16-Sep-2002  23:12  2000.80.686.0      98,872 bytes  Xpweb70.dll 
				

Note Because of file dependencies, the most recent hotfix or feature that contains the files may also contain additional files.


MORE INFORMATION

The behavior can be triggered by snap shot backups because the snap shot backup process involves the freeze and thaw of input/output (IO) operations. The freeze activity holds up all physical IO activity until the thaw is issued at the end of the snap shot backup operation. In doing so, a code change made in SQL Server 2000 Service Pack 2 (SP2) results in heavier CPU usage than previous versions of SQL Server. The scalability change in SQL Server 2000 SP2 makes the log code scale better on multi-CPU computers; however, it can result in heavier CPU usage under these rare conditions.
For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

818767 FIX: Improved CPU Usage for Database Logging When Transaction Log Stalls Occur


Modification Type:MinorLast Reviewed:10/11/2005
Keywords:kbHotfixServer kbQFE kbfix kbbug KB813645