Microsoft KB Archive/873482

= FIX: The restore process may take longer to complete when SQL Server 2000 restores transaction log files as part of the log shipping process =

Article ID: 873482

Article Last Modified on 11/2/2007

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APPLIES TO


 * Microsoft SQL Server 2000 Developer Edition
 * Microsoft SQL Server 2000 Standard Edition
 * Microsoft SQL Server 2000 Enterprise Edition
 * Microsoft SQL Server 2000 Personal Edition
 * Microsoft SQL Server 2000 Enterprise Edition
 * Microsoft SQL Server 2000 Workgroup Edition
 * Microsoft SQL Server 2000 Desktop Engine (Windows)
 * Microsoft SQL Server 2000 Developer Edition
 * Microsoft SQL Server 2000 Enterprise Edition 64-bit

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Bug #: 470244 (SQL Server 8.0)



Article contents
 Summary Symptoms Resolution 

Service pack information

 

Hotfix information

 

Prerequisites

 

Restart information

</li> 

Hotfix file information

</li> Status</li> More Information</li> 

Factors that affect the speed of the restore process

</li> 

The memory blocks that are fetched in the data cache

</li> 

The Virtual log file size

</li> 

The parallel query processing operations

</li> 

The BufferCount parameter

</li></ul>

<div class="summary_section">

SUMMARY
This article describes the following about this hotfix release:
 * The issues that are fixed by this hotfix package.
 * The prerequisites for installing the hotfix package.
 * Whether you must restart your computer after you install the hotfix package.
 * Whether the hotfix package is replaced by any other hotfix package.
 * Whether you must make any registry changes.
 * The files that are contained in the hotfix package.

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<div class="symptoms_section">

SYMPTOMS
When the transaction log files of your database are restored by using the WITH RECOVERY option as part of the log shipping process, you may notice that Microsoft SQL Server 2000 takes longer to complete the restore operation successfully than you expect.

For a list of previous hotfixes, see the &quot;Microsoft SQL Server 2000 post-Service Pack 3 or Microsoft SQL Server 2000 post-Service Pack 3a hotfixes&quot; section in the following Microsoft Knowledge Base article:

290211 How to obtain the most recent SQL Server 2000 service pack

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<div class="resolution_section">

Service pack information
To resolve this problem, obtain the latest service pack for Microsoft SQL Server 2000. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

290211 How to obtain the latest SQL Server 2000 service pack

Prerequisites
This hotfix requires Microsoft SQL Server 2000 Service Pack 3 (SP3). For information about how to obtain SQL Server 2000 SP3, see the following article in the Microsoft Knowledge Base:

290211 How to obtain the most recent SQL Server 2000 Service Pack

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Restart information
You do not have to restart your computer after you apply this hotfix.

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Hotfix file information
This hotfix contains only those files that are required to correct the issues that this article lists. This hotfix may not contain all the files that you must have to fully update a product to the latest build.

The English version of this hotfix has the file attributes (or later file attributes) 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. <pre class="fixed_text">  Date         Time   Version            Size    File name ---  15-Jul-2004  16:12  2000.80.961.0     664,128  Autoplt.dll 15-Jul-2004 16:27  2000.80.961.0      78,400  Console.exe 15-Jul-2004 16:44  2000.80.961.0     315,968  Custtask.dll 15-Jul-2004 16:12  2000.80.961.0      33,340  Dbmslpcn.dll 08-Apr-2004 09:12                    786,432  Distmdl.ldf 08-Apr-2004 09:12                  2,359,296  Distmdl.mdf 10-Oct-2003 06:18                        180  Drop_repl_hotfix.sql 15-Jul-2004 16:40  2000.80.961.0   1,905,216  Dtspkg.dll 15-Jul-2004 16:37  2000.80.961.0     528,960  Dtspump.dll 15-Jul-2004 16:53  2000.80.961.0   1,557,052  Dtsui.dll 15-Jul-2004 16:52  2000.80.961.0     639,552  Dtswiz.dll 10-Oct-2003 06:18                    747,927  Instdist.sql 10-Oct-2003 06:18                      1,581  Inst_repl_hotfix.sql 15-Jul-2004 16:59  2000.80.961.0     352,828  Isqlw.exe 15-Jul-2004 16:53  2000.80.961.0      82,492  Itwiz.exe 15-Jul-2004 16:11  2000.80.961.0      90,692  Msgprox.dll 19-May-2004 11:13  8.11.40209.0      209,408  Mssdi98.dll 15-Jul-2004 16:14  2000.80.961.0      62,024  Odsole70.dll 15-Jul-2004 16:32  2000.80.961.0      25,144  Opends60.dll 15-Jul-2004 16:13  2000.80.961.0      57,904  Osql.exe 15-Jul-2004 16:41  2000.80.961.0     279,104  Pfutil80.dll 10-Oct-2003 06:07                    550,780  Procsyst.sql 08-Apr-2004 09:12                     12,305  Qfe469315.sql 08-Apr-2004 09:12                     19,195  Qfe469571.sql 15-Jul-2004 17:43                  1,105,167  Replmerg.sql 15-Jul-2004 16:21  2000.80.961.0     221,768  Replprov.dll 15-Jul-2004 16:23  2000.80.961.0     307,784  Replrec.dll 15-Jul-2004 16:14  2000.80.961.0     159,813  Replres.rll 10-Oct-2003 06:18                  1,087,150  Replsys.sql 10-Oct-2003 06:18                    986,603  Repltran.sql 15-Jul-2004 16:27  2000.80.961.0     287,304  Rinitcom.dll 15-Jul-2004 16:12  2000.80.961.0      78,416  Sdiclnt.dll 15-Jul-2004 16:01  2000.80.961.0      66,112  Semmap.dll 15-Jul-2004 16:06  2000.80.961.0      57,916  Semnt.dll 15-Jul-2004 16:50  2000.80.961.0     492,096  Semobj.dll 15-Jul-2004 16:45  2000.80.961.0     172,032  Semobj.rll 15-Jul-2004 16:20  2000.80.961.0      53,832  Snapshot.exe 13-Jul-2004 08:29                    117,834  Sp3_serv_uni.sql 15-Jul-2004 16:06  2000.80.961.0      28,672  Sqlagent.dll 15-Jul-2004 16:10  2000.80.961.0     311,872  Sqlagent.exe 15-Jul-2004 16:16  2000.80.961.0     168,001  Sqlakw32.dll 15-Jul-2004 16:16  2000.80.961.0      33,344  Sqlctr80.dll 15-Jul-2004 16:52  2000.80.961.0   4,215,360  Sqldmo.dll 15-Jul-2004 16:19                     25,172  Sqldumper.exe 15-Jul-2004 16:02  2000.80.961.0      28,672  Sqlevn70.rll 15-Jul-2004 16:22  2000.80.961.0     156,224  Sqlmaint.exe 15-Jul-2004 16:25  2000.80.961.0     180,792  Sqlmap70.dll 15-Jul-2004 16:50  2000.80.961.0     188,992  Sqlmmc.dll 15-Jul-2004 16:46  2000.80.961.0     479,232  Sqlmmc.rll 15-Jul-2004 16:44  2000.80.961.0     401,984  Sqlqry.dll 15-Jul-2004 16:23  2000.80.961.0      57,920  Sqlrepss.dll 15-Jul-2004 16:16  2000.80.961.0   7,512,640  Sqlservr.exe 15-Jul-2004 16:04  2000.80.961.0     590,396  Sqlsort.dll 15-Jul-2004 16:24  2000.80.961.0      45,644  Sqlvdi.dll 15-Jul-2004 16:23  2000.80.961.0     106,588  Sqsrvres.dll 15-Jul-2004 16:12  2000.80.961.0      33,340  Ssmslpcn.dll 15-Jul-2004 16:13  2000.80.961.0      82,492  Ssnetlib.dll 15-Jul-2004 16:30  2000.80.961.0      25,148  Ssnmpn70.dll 15-Jul-2004 16:25  2000.80.961.0     123,456  Stardds.dll 15-Jul-2004 16:26  2000.80.961.0     158,240  Svrnetcn.dll 15-Jul-2004 16:26  2000.80.961.0      76,416  Svrnetcn.exe 15-Jul-2004 16:30  2000.80.961.0      53,808  Ums.dll 15-Jul-2004 16:27  2000.80.961.0      98,872  Xpweb70.dll

Note Because of file dependencies, the most recent hotfix that contains these files may also contain additional files.back to the top

<div class="status_section">

STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the &quot;Applies to&quot; section.

This problem was first corrected in Microsoft SQL Server 2000 Service Pack 4.

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<div class="moreinformation_section">

MORE INFORMATION
The SQL Server Agent job that corresponds to the log shipping process runs the xp_sqlmaint extended stored procedure that invokes the sqlmaint utility to restore the transaction log files.

The hotfix that is discussed in this article adds the following new parameters to the sqlmaint utility to help users speed up the restore process:
 * MaxTransferSize
 * BufferCount

To improve the performance of the restore operation, you can modify the SQL Server Agent job step that calls the xp_sqlmaint extended stored procedure. Include the MaxTransferSize and the BufferCount parameters as the input parameters for the extended stored procedure. A command line that specifys a 512 KB transfer size with 2 buffers appears as follows:

-MaxTransferSize 524288 -BufferCount 2

Factors that affect the speed of the restore process
Several factors can affect the speed of the restore process. You must consider the following factors when you are evaluating the performance of the restore process:
 * The memory blocks that are fetched in the data cache.
 * The Virtual log file size.
 * The parallel query processing operations.

More information about each of these factors follows.

The memory blocks that are fetched in the data cache
The data pages that correspond to your database are not in the SQL Server data cache at the time that you initiate the restore process. The restore process uses the read-ahead feature to issue the asynchronous I/O. Therefore, the required data pages are fetched from the memory to the data cache in advance.

The data pages are fetched from the memory to the data cache in memory blocks. By using the MaxTransferSize parameter of the sqlmaint utility, you can adjust the size of the memory block that is fetched from the memory to the data cache during the restore operation. The maximum value that can be set for the MaxTransferSize parameter is 4,194,304. Therefore, the maximum size of the memory block that can be fetched from the memory to the data cache is 4 MB.

Note The value that is set for the MaxTransferSize parameter must be a power of 2, and the value must be between 64 KB and 4 MB, specified in bytes.

The more the data is available to SQL Server for processing during the restore process, the more speed the restore process will have. By using the MaxTransferSize parameter, you can increase the buffer size that can be fetched from the memory to the data cache by the read ahead operation. This will help improve the performance of the restore process.

For more information about how to improve the capabilities of the read ahead features, click the following article number to view the article in the Microsoft Knowledge Base:

834451 FIX: Restoring transaction log files takes longer than expected in SQL Server 2000

<div class="moreinformation_section">

The Virtual log file size
Each transaction log file is logically divided into smaller segments that are referred to as virtual log files. All the virtual log files are not necessarily of the same size, and they are not in the same physical memory order. Therefore, the size of the memory block that is fetched during the read ahead operation depends on the size of the current virtual log file. Increasing the value of the MaxTransferSize parameter may not have any effect on the speed of the restore process of the transaction log files that contain smaller virtual log files.

For optimal performance, we recommend that you manually shrink the transaction log files instead of letting Microsoft SQL Server 2000 automatically shrink the transaction log files. Additionally, you must set the file growth increment size or the file growth increment percentage to a reasonable size to prevent the transaction log file from growing by too small a value.

For more information, visit the following Microsoft Web site:

http://msdn2.microsoft.com/en-us/library/aa174524(SQL.80).aspx

<div class="moreinformation_section">

The parallel query processing operations
This is an important factor when you are evaluating the performance of the restore operation. Because SQL Server accomplishes the restore operation by using a single execution thread, a parallel query processing operation that is recovered during the restore process takes longer. For example, a parallel query processing operation that takes 1 second to complete on an eight processor computer will take 8 seconds to complete during the restore process. Therefore, you must evaluate the requirements of the parallel query processing operations when you are backing up the log files by using the log shipping process.

<div class="moreinformation_section">

The BufferCount parameter
The hotfix that is discussed in this article also includes an optional BufferCount parameter for the sqlmaint utility. You can use the BufferCount parameter to change the number of memory blocks that are the size as specified by the MaxTransferSize parameter and that are fetched by the read ahead feature at one instance. By default, the BufferCount parameter is set to 3.

However, note that the BufferCount parameter can be used only when you restore your SQL Server database. When you restore your SQL Server log, the log restore process disregards the value and it considers the default buffer count to be 3, even though you set the value of the BufferCount parameter to a value other than the default value.

Note The expression (BufferCount * MaxTransferSize) evaluates to the memory size that is fetched to the data cache. Therefore, maximizing these values may not always be a good solution. Make sure that you work with a reasonable memory goal.

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For additional information about the naming schema for Microsoft SQL Server updates, click the following article number to view the article in the Microsoft Knowledge Base:

822499 New naming schema for Microsoft SQL Server software update packages

For additional information about the terminology that Microsoft uses when correcting software after it is released, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

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Additional query words: arguments switches recover

Keywords: kbbug kbfix kbcaching kbperformance kbqfe kbsqlserv2000presp4fix kbhotfixserver KB873482

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