Nextcloud 19 - cron.php + postgres produce constant high load


my UCS instance was installed with Nextcloud 17 or older. Since I upgraded to Nextcloud 19, there is a constant high load (>5). The system is a KVM instance with 4 cores and 16 GB RAM which is used by <5 users.

Symptomps are similar to

  • several cron.php tasks in parallel (currently 5)
  • postgres often in “top”

The whole system is dead slow now. Where can I debug what cron.php actually does?

Update: Looking at “lsof” for the cron.php it seems like Nextcloud is re-indexing my music (several thousand mp3 files).