Rudder

Clicking on "Regenerate all policies" clears all the caches, even the expensive changes cache (all changes made by the rules)
So it starts querying the database to get them over the last 3 days, and it can be very large, and slow to gather (with out of the box config, 2000 nodes and millions changes, it takes 4 minutes) - and it slows down everything

I don't see why Regenerating all policies would clear this cache.