Thanks a lot @lonvia for this quick improvement.
I will give it a try shortly to see how it matches the views of the project.
It has to be said that recent tries shown that we could process up to 30 days of daily diff to not be stuck by performance versus OSH extract (see the chart here ProjetDuMois/docs/DEVELOP.md at master · vdct/ProjetDuMois · GitHub). So we work around by limiting the use of diffs by 30 days ago the current date for now. But querying diffs in the past could definitely be useful for punctual enrichment or measures of the existing log file.