I have fixed my issue with the cron, at least for now. Using strace -p PID for the process never finishing I realised that it was going over my appdata_xxx/preview folder and was never able to finish this.
Based on the files_cache database I had more than 3 158 958 entries linking to the preview. I assume I had even more files in there. I followed a “not so recommended” procedure to get rid of the folder and the database entries and it worked (but took forever).
Still there are open questions
- Why the hack do I have millions of entries for preview in there? I have lots of pictures, but if this is an “overall” bottleneck this should be solved differently.
- Why the hack are all files, including previews, scanned twice a day using the
jobsdatabase? OR is it even more often? This is my biggest concern, question, whatsover part of this - WHY ? Bigger system must suffer from this too, I just don’t get it. - How does the
jobsdatabase work, what do the entries mean, any documentation appreciated. - And why is nobody jumping in from the DEVs helping out, I thought this is a support forum where even DEVs from the Nextcloud Team help out?