NonStop ODBC: how the connections (ODBC servers) are assigned to CPUs?

Question

We have an ODBC pool running on a NonStop server. The pool is connected to SQL/MX.

This pool is used by a few external Java applications, each of which has an JDBC pool connected to ODBC pool (e.g. 14 connections per application).

With time (after a few application recycles) we see an imbalance between CPUs -- some have 8 ODBC processes running, some only 5. That leads to CPU time imbalance too.

Up to this point we assumed that a CPU is assigned to ODBC process in round-robin fashion. That would maintain the number of ODBC processes more or less equally distributed. It's not the case though.

Is there any information on how ODBC pool decided which CPU to choose for every new allocated process? Does it look at CPU load? Available memory? Something else?

Sadly, even HP's own people (available to us, that is) couldn't answer those questions with certainty. :-(

Answer 1

And in fact connections are assigned to CPUs in round-robin fashion. But if one of the consumers (with its own pool) is restarted for any reason, the connections will be released on the CPUs where they were allocated (obviously), but new ones will be allocated on the next CPU according to round-robin algorithm. Thus some CPUs will become less busy, and some more. Thus imbalance.