Pooling the Microsoft ODBC driver for IBM DB2 with MTS/COM+ (313331)

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256986 Description of the Microsoft Windows Registry

SUMMARY

Microsoft Transaction Server (MTS) and Microsoft COM+ enable Open Database Connectivity (ODBC) connection pooling by default. An MTS/COM+ application does not need to explicitly enable ODBC connection pooling. However, when you use the Microsoft ODBC Driver for DB2 that comes with Host Integration Server (HIS) 2000, you need to perform an extra configuration step to enable ODBC connection pooling in MTS/COM+ applications.

This article assumes that you are developing MTS/COM+ components using ActiveX Data Objects (ADO) that are registered under MTS/COM+.

MORE INFORMATION

MTS/COM+ components that use ADO communicate with the Microsoft ODBC Driver for DB2 by using the Microsoft OLE DB Provider for ODBC Drivers (MSDASQL). For ODBC connection pooling to work with the Microsoft ODBC Driver for DB2, you must turn off OLE DB session pooling for the MSDASQL provider. With Microsoft Data Access Components (MDAC) version 2.1 and later, OLE DB session pooling is turned on by default.

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To turn off OLE DB session pooling for MSDASQL, follow these steps:

Start Registry Editor (Regedt32.exe).
Locate the OLEDB_SERVICES value under the following key in the registry:
HKEY_CLASSES_ROOT\CLSID\{c8b522cb-5cf3-11ce-ade5-00aa0044773d}\
On the Edit menu, click DWORD, type 0xfffffffc, and then click OK.
Quit Registry Editor.

NOTE: If you make this change in the registry, it affects all applications that are using the MSDASQL provider. To avoid this, you can also set this value in your application by adding the value OLE DB SERVICES=-4 in your connection string to turn off OLE DB session pooling and autoenlistment. This setting turns off these properties for the OLE DB provider, and allows the pooling and autoenlistment to occur at the ODBC driver level.

For more information about ODBC connection pooling, click the following article numbers to view the articles in the Microsoft Knowledge Base:

237844 How to enable ODBC connection pooling in a Visual Basic ADO application

245543 ODBC Connection pooling counters in Performance Monitor and ADO

169470 Frequently asked questions about ODBC connection pooling