Multi-thread failure - Error in assignment

Question

Hello
I have a c++ program processor running under Windows XP with Oracle 9i. My program access to oracle by an ODBC driver version 9.2.0.4.0. It could be launched in multi-thread to increase performance. When I launch it with one thread everything is fine. When I use several threads I have problems. ODBC driver returns to me a "error in assignment ... General error" message and my updates queries failed. Under SQl server it works without problems. It seems to be a kind of deadlock. When I disable check box in my odbc driver of "enable query timeout" my program encounter a problem and freezes...
Could someone help me ?

Answer 1

user13335017 wrote:
I have thought of the above solutions as workable, however, it is not. Some exhibited errors are:
A. "Attempt to use database while environment is closed." This error applies to 2, 3 and 4 all the way;
B. "Attempt to read / write database while database is closed." This error applies to 3 in particular;
C. "Attempt to close environment while some database is still open." This error applies to 5.
Please help me with designing a better strategy to solve the concurrent issue. Many thanks in advance.All these are expected errors. You should design the application so that you do not close an environment handle while database handles are still open, keep database handles open for as long as operations need to be performed on the underlying databases, open the database handles after opening the database handles, and close database handles before closing the environment handle.
In short, in pseudo-code, you should have something like this:
- open environment handle,
- open database handles,
- perform whatever operations are needed on the databases,
- close database handles,
- close environment handle.
You can refer to the Getting Started with Data Storage and the Getting Started with Transaction Processing guides appropriate for the API you are using, from the Berkeley DB documentation page.
Regards,
Andrei