Easysoft ODBC-ODBC Bridge

Why does my second connection to MS Access hang?

Last Reviewed:
27th October 2008

You may notice if you try attaching a MS Access ODBC driver data source to the MS Access application in windows that it does not let you do this. Easysoft have seen problems making more than one simultaneous connection from UNIX through the OOB to the MS Access ODBC driver (specifically hanging). We think that the MS Access ODBC driver dll may contain some shared data that is incompatible with our default configuration of a multi-threaded OOB server. You can work around this problem by changing the OOB Server to run multi-process instead of multi-threaded.

According to Microsoft's web site (http://support.microsoft.com/kb/842277)

Known Issue: ODBC Jet driver in multithreaded environments
Component: ODBC Jet driver

When running in a multithreaded or stress environment such as IIS, it is recommended not to use ODBC because of issues with threading in the driver as well as the Jet engine. The recommendation for this situation is to work with the OLE DB provider for Jet.

To make the OOB Server run multi-process instead of multi-threaded use the OOB Server administration interface by browsing http://mywindowsmachine:8890. Select Configuration, Change Configuration and then check the MultiProcess checkbox. Click on submit. If the OOB Server configuration page had an "AutoUpdateConfiguration" checkbox and it was not checked you will need to restart the OOB Server Service. Versions of the OOB Server administration interface without the "AutoUpdateConfiguration" checkbox do not need the service restarting.

Update to this. According to Microsoft's web site JET 4 is now thread-safe:

Frequently Asked Questions About ODBC Connection Pooling

You can ascertain if you have JET 4 by clicking on the drivers tab in Control Panel -> DataSources and examining "Microsoft Access Driver". If it says 4.xxxx then you should not need to switch the OOB Server in to MultiProcess mode (as detailed above).

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