Microsoft KB Archive/915307

= FIX: You experience a slow uploading process if conflicts occur when many merge agents upload changes to the publishers at the same time in SQL Server 2005 =

Article ID: 915307

Article Last Modified on 11/4/2007

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APPLIES TO


 * Microsoft SQL Server 2005 Standard Edition
 * Microsoft SQL Server 2005 Developer Edition
 * Microsoft SQL Server 2005 Workgroup Edition
 * Microsoft SQL Server 2005 Enterprise Edition

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Bug #: 379 (SQL Hotfix)

Bug #: 421633 (SQLBUDT)



Notice
Microsoft distributes Microsoft SQL Server 2005 fixes as one downloadable file. Because the fixes are cumulative, each new release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2005 fix release.



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
 * Information about whether you must restart the computer after you install the hotfix package
 * Information about whether the hotfix package is replaced by any other hotfix package
 * Information about whether you must make any registry changes
 * The files that are contained in the hotfix package



SYMPTOMS
You have many merge agents in SQL Server 2005. For example, you have 500 merge agents. When these merge agents upload changes to the publishers at the same time, you experience a slow uploading process. In some cases, the uploading process never finishes.

This problem occurs if conflicts occur when these merge agents upload changes.



CAUSE
This problem occurs because the following behavior occurs when the merge agents try to log conflicts during the upload process:
 * When a merge agent queries the MSmerge_conflicts_info table, the query optimizer performs an Index Scan on the table instead of a Clustered Index Seek on the table.
 * No index is defined on the MSmerge_conflict_ _  table. When a merge agent queries the table, the query optimizer performs a Table Scan. When these merge agents log conflicts, SQL Server frequently queries the table. However, a Table Scan consumes lots of time if the table is big.

Additionally, a deadlock occurs in the following scenario:
 * One merge agent holds a lock on a user table at the publisher.
 * The merge agent requests a lock on the MSmerge_conflict_ _  table.
 * At the same time, another merge agent holds a lock on the MSmerge_conflict_ _  table and requests a lock on the same user table.

In this scenario, the merge agents block one another.

If a deadlock occurs, the uploading process never finishes.



Service pack information
To resolve this problem, obtain the latest service pack for SQL Server 2005. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

913089 How to obtain the latest service pack for SQL Server 2005

Hotfix information
A supported hotfix is now available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Prerequisites
You must have SQL Server 2005 installed to apply this hotfix.

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

Registry information
You do not have to change the registry.

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 of 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 item in Control Panel.

Actions to take after you apply this hotfix
After you apply this hotfix, follow these steps:  Start SQL Server Management Studio, and then connect to the instance of SQL Server 2005. Expand Replication, and then expand Local Publications. Regenerate the snapshots for all the publications.

To do this, follow these steps:  Right-click the publication that you want to regenerate the snapshot, and then click View Snapshot Agent Status. In the View Snapshot Agent Status dialog box, click Start.</li></ol> </li> Reinitialize the subscriptions to the publications.

For more information about how to reinitialize a subscription, visit the following Microsoft Developer Network (MSDN) Web site:

http://msdn2.microsoft.com/en-us/library/ms152466.aspx

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STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section. This problem was first corrected in SQL Server 2005 Service Pack 1.

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MORE INFORMATION
This hotfix optimizes the query against the MSmerge_conflicts_info table. The hotfix does this by enhancing the WHERE clause in the query to include all the index key columns of the table. If you only apply this hotfix to resolve the problem that is described in the &quot;Symptoms&quot; section, you do not have to restart the SQL Server service.

For more 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 more information about software update terminology, 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

Keywords: kbbug kbsql2005sp1fix kbsql2005repl kbhotfixserver kbfix kbexpertiseadvanced kbqfe kbpubtypekc KB915307

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