Tracing missing data
After quite a while of debugging and testing (we got permission to turn on a bit more logging on our customers machine) I found out that the disappearing data is received by the second component but not processed.
Yesterday evening I found out why:
The processing of the data in our classes is done with the help of a Visitor Design Pattern. This was engineered by a former collegue of me but not in a easy recognizable way.
And so it came that a very specific situation could occour and the data slipped through all processing untouched.
Fixed it and after a new release (presumably on next monday evening/night), we should be down to 0,000005 percent of missing data. 10 records in two million which still disappear without any apparent reason.
And tomorrow night we'll fully convert the system where we partially released last friday.