hi, monetdb has always held ram after completing an operation on windows. my solution has always been to simply close and re-open mserver.
hannes is now working on monetdblite, which if successful is going to attract lots of new users who aren't going to know that they need to close & re-open the server after any big operation.
i have uploaded a video to youtube detailing this problem. it just shows the same csv being imported ten times into ten distinct tables. each time the ram monitor ticks up 0.3gb and never comes back down. the entire operation holds 3gb of ram.