Multithreaded ODBC SP call locking problem

I'm looking at a problem talking to MS-SQL. My program holds open several (typically 4) connections to the database.  Each connection is managed by a thread in the app, which queues and sends requests to execute a stored procedure.

The SP is the same every time, and there is no data-driven conditional logic, just the following sequence of ODBC calls:  SQLAllocHandle; SQLBindCol; SQLBindCol; SQLFetch; SQLCloseCursor; SQLFreeHandle; SQLEndTran.

This works for ages (10s or 100s of thousands of times), but very occasionally the SP finishes but does not commit open transactions.  We can see SQL Server sending the output parameter over the network, so we're sure the SP is complete, but the program doesn't seem to send back the SQLEndTran request.  The result is locks in the database which cause other problems.

Searching through the archives I found this post: http://lists.ibiblio.org/pipermail/freetds/2009q4/025439.html

...which mentions UnixODBC threading and a known problem.

So finally my question: I was wondering what the referenced problem is and if it might cause the problem I'm looking at?  Also, if anyone has any ideas as to what I might look at, I would be very interested to hear them.

freetds-0.62.4  (I know, I'm sorry, it's very old.  Not my choice!)
unixODBC-2.2.11

P.S. Greetings FreeTDS mailing list!  My first post.




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