SUMMARY For a sufficiently large photo collection, "Clear and rebuild all training data" for face recognition takes a lot of time. If digiKam is restarted during the process, the process seems to be stopped (incomplete?, cancelled? undone?) without any messages and explanations, and does not resume in order to get properly finished. STEPS TO REPRODUCE 1. Have a large collection of images with marked faces. 2. Tools -> Maintenance -> Clear and rebuild all training data 3. Let it run to 10%. 4. Close digiKam. 5. Open digiKam. OBSERVED RESULT When closing, no warning about interrupting face rebuilding process and information about consequences. When digiKam is reopened, nothing happens, no maintenance process is resumed. EXPECTED RESULT When digiKam is reopened, the face DB rebuilding process should be resumed. If not, at least a warning about interrupting face rebuilding process and information about consequences should be displayed when closing digiKam. In my opinion, an even better UX approach would be if the rebuilding process could be done in the background, on demand – as soon as any face-related data gets changes (e.g., the user confirms a new face), so the user does not have to worry about existence of such maintenance commands, and when or whether they should be executed. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Mint 20.1 KDE Plasma Version: KDE Frameworks 5.68.0 Qt 5.12.8 (built against 5.12.8) ADDITIONAL INFORMATION
No maintenance tasks will be continued at the next start if they were not complete, including creating thumbnails or fingerprints, etc. You also do not need to constantly rebuild the training data, only when we have made major changes to the face engine. If you provide images with face regions / tags, the training database is automatically updated with the newly created faces. A warning when exiting would be conceivable ... Maik
OK, thank you for explaining that I don't have to use it. In that case, there could be some kind of notification (upon opening digiKam or maybe when opening some maintenance window where there is a list of things waiting to be done) if there have been some major changes to the engine, so users know that they need to run the command. So, if I've quit digiKam while it's rebuilding the training data, the face recognition is not working to its best, right? Maybe that notification could better be displayed upon executing the maintenance command, not upon closing digiKam.