Microsoft KB Archive/181776

= FIX: Locking Problem When Using XA Transactions =

Article ID: 181776

Article Last Modified on 9/23/2005

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APPLIES TO


 * Microsoft Transaction Services 2.0

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This article was previously published under Q181776



SYMPTOMS
Microsoft Transaction Server causes database blocking problems when transactions are used against XA-compliant databases, including Oracle and DB/2. If two or more Microsoft Transaction Server components that share a transaction open connections to the same database and try to access the same database records or index sets, they collide on locks.



CAUSE
This problem occurs because of the way that Msdtcprx.dll generates the XA Transaction ID (XID). The XID has two parts: a Global Transaction ID (GTRID) and a Branch Qualifier (BQUAL). The XIDs contain three GUIDs. For Microsoft Transaction Server version 2.0, all three GUIDs are located in the GTRID and the BQUAL is empty. However. the first GUID should be in the GTRID and the other two GUIDS in the BQUAL. Therefore, to XA, each connection looks like it is working on a different transaction. By generating the XA XID in the new way, all of the connections work on the same transaction.



STATUS
Microsoft has confirmed this to be a problem in Microsoft Transaction Server version 2.0. This problem has been fixed in Microsoft Windows NT 4.0 Service Pack 4 (SP4).

Keywords: kbbug kbfix kbqfe kbdatabase kbhotfixserver KB181776

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