Hi !

Without dropping tables (but then why to bother with partitioning?) the tables can take indeed 2 TB if
- you have loaded there ~20TB of data, so 2 TB are there in the compressed form on disk
- every columns takes the same disk space

Normally there are a few wide columns taking a lot of space and a few narrow ones, possibly low cardinality (e.g. numbers, enums) compressed very well. Then the wide columns get contained in e.g. 10 data files, so 8 of them can be deleted, why the narrow column take 1-2 files, but each file is much smaller than 2GB.