12.1.5. Tracing XA calls in OpenLink ODBC Drivers
When logging is enabled in an XA-enabled OpenLink ODBC driver, an XA log file is opened in addition to the usual ODBC log file. For instance, when using a Windows Lite driver, if you specify a log file name of c:\ntl6o10zu.log in the Lite setup dialog, an XA log file named c:\ntl6o10zu.log-xa will also be created. Because all DSNs which use the same OpenLink driver share the same log file name, if two applications use the same driver simultaneously, the log output from one application will be lost. The last application to connect takes ownership of the log file. This problem can be overcome by including meta-characters in the log file name. This is an OpenLink v6 feature which allows applications to have their own log file. The meta-characters substitute additional information into the log file name. They can also be used when configuring logging for a OpenLink ODBC Lite driver or an OpenLink ODBC generic multi-tier client, on both Windows or Unix.)
Supported meta-characters are:
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$$ - inserts $ (Windows & Unix)
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$P - current process id (Windows & Unix)
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$U - inserts user name (Windows & Unix)
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$H - inserts C:\ (Windows) or user's home directory (Unix)
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$T - timestamp (yyyymmdd-hhmmss) (Windows & Unix)
For instance, when tracing XA, it is useful to include $P, e.g. c:\ntl6i10zu_$P.log, so that each process using the driver gets its own XA log file. This is important when using the MS DTC as the transaction monitor, as the DTC loads the ODBC driver at the same time as the application when connecting to an RM through ODBC.