Replaced the broken, but quick, handle lifetime generating code and got correct results from the ops file. Which is good, since I don't have to regenerate the ops file each time.
However, the histogram generation code is, as noted yesterday, naive and runs in O(n2), which turns out to take a lot of time processing 8 Gb data. I modified the original code based on what I had now - working - and got code that runs in O(n) instead, still generating the same results for the small dataset of LibreOffice-188.8.131.52 opening an empty database file.
Checking out after 2h48m,