Unexpected NO_DATA_FOUND exception corrupting data

Question

First off:
Application Express 4.0.2.00.06 on Solaris
Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64bit Production
I'm having a very frustrating, intermittent, non-replicable problem with my ApEx application. I have seen about two dozen instances of this issue in the last 6 months. From the best of my debugging abilities, it appears that within one of my page processes is a very simple select with one bound variable (see below) that is throwing the "NO_DATA_FOUND" exception even though I know there is exactly one matching row. The data we are querying for was inserted in a transaction which was committed 18 hours prior (in the most recent case).
BEGIN
SELECT status INTO l_status FROM orders o, status s WHERE o.status_id=s.status_id AND o.order_id=:P11_ORDER_ID;
EXCEPTION WHEN NO_DATA_FOUND THEN
l_status := '';
END;
The expected result is l_status == 'OPEN' (1), but instead we're getting a null value. All of my trigger-based audit logs, debugging log, and the flashback data indicate that value of :P11_ORDER_ID is correct, the matching row existed, and o.status_id was set to integer value 1 during the time that the error occurred.
Are there any other reasons for this exception to be raised?
I've updated my debugging messages to confirm that the exception code is the source of the null value, but now I have to wait for another week or two to hopefully get the results of that test.
Thanks,
Jason Gullickson

Answer 1

Update -- we had another run in with this issue today, and the updated debugging message confirmed that the error message was indeed "ORA-01403: no data found" and code was 100.
Once again, the row existed, the query id was correct, and the target column was not null -- and yet we were given the NO_DATA_FOUND exception.
-Jason