I deleted all archived cases but in the database arc_ tables have a lot of data in them


I deleted all archived cases in the bonita portal, but if i check my database only in my arch_flownode table i have more than 2 million records. Is this a bug? Or somewhere the app malfunctioned, and didnt delete the process instances? Is it safe to just delete all data from the arc_ tables?

Or is it normal to keep these records even if you dont need them?