FIX: The synchronization process is slow, and the CPU usage is high on the computer that is configured as the Distributor in SQL Server 2005

When you synchronize a subscription to a transactional replication publication in Microsoft SQL Server 2005, the synchronization process is slow. During the synchronization process, the CPU usage is high on the computer that is configured as the Distributor.

This problem occurs if the following conditions are true:

• The MSrepl_commands table contains many rows for the publisher database. For example, the MSrepl_commands table contains 800,000 rows for the publisher database.
• The synchronization process initializes the Subscriber or reinitializes the Subscriber. Alternatively, you incrementally add an article to the publication before you synchronize the subscription.

Note This problem is not specific to transactional replication in SQL Server 2005. This problem may also occur for any query if the following conditions are true:

• You query a table that contains many rows. For example, the table contains 800,000 rows.
• You use the FAST query hint or the TOP query hint in the query.

This problem occurs because SQL Server 2005 generates an inefficient execution plan for one of the queries in the sp_MSget_repl_commands stored procedure. This problem occurs only if the query that performs poorly uses the FAST query hint or the TOP query hint. The execution plan for the query that performs poorly shows that a join predicate is not pushed down to a Clustered Index Seek operator.

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:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in SQL Server 2005 Service Pack 3.

This hotfix introduces trace flag 4126. You must enable this trace flag to resolve this problem. To enable this trace flag, use the DBCC TRACEON statement, or specify trace flag 4126 as a startup parameter for the SQL Server service.

For more information about the same issue that occurs in SQL Server 2000, click the following article number to view the article in the Microsoft Knowledge Base:
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: