Microsoft Distributed Transaction Coordinator Does Not Flush Log Records Efficiently (306365)

SYMPTOMS

During a Transaction Processing Performance Council (TPC) benchmark test, Microsoft Distributed Transaction Coordinator (MS DTC) spends 50 percent of its time flushing log records to disk. MS DTC also spends approximately 10 percent of its time moving active connection objects from the active list to the free list.

CAUSE

The log manager has a single flush thread to flush log record pages to disk for all transactions. After the page is on the disk, the flush thread notifies all of the transactions whose records have been flushed. This single thread that notifies the transactions does not scale well on high-end enterprise scenarios.

While MS DTC holds a connection object and a spin lock, MS DTC searches the active list of connection objects in a linear fashion and moves this object to a free list.

RESOLUTION

To resolve this problem, obtain Microsoft COM+ hotfix rollup package 18.2. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

317177 INFO: Availability of Windows 2000 Post-Service Pack 2 COM+ Hotfix Rollup Package 18.2

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

260910 How to Obtain the Latest Windows 2000 Service Pack

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows 2000 Service Pack 3.

MORE INFORMATION

COM+ hotfix rollup package 18.2 improves MS DTC performance by four or five percent in a recent benchmark test. For more information, refer to the following Microsoft Web site:

Microsoft SQL Server Scales Up and Scales Out
http://www.microsoft.com/presspass/Press/2001/Sep01/09-20SQLBenchmarkPR.asp

For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173 The Datacenter Program and Windows 2000 Datacenter Server Product

For additional information about how to install multiple hotfixes with only one reboot, click the article number below to view the article in the Microsoft Knowledge Base:

296861 Use QChain.exe to Install Multiple Hotfixes with One Reboot