I try to work in CartoDB with data I import from CSVs (or xlsx, see below). The data is 24.1 MB in ASCII CSV, 10 MB in xlsx.
I spent quite some time shrinking my data's size, and I was happy to upload less than 25 MB (the limit of my free academic account). I am puzzled by what happened next. I could delete two longish string columns (latitude and longitude, as cartodb georeferenced it automatically). I could convert a column of years to numbers from strings, which should only shrink the size of the table. I could convert a column of dates string to date, which should shrink it further. But when I would do one final operation I need, the conversion of an intensity measure of my temporal heat map from string to number, which can only shrink the size further, THEN cartodb complains that I am over the limit of my account? I spent hours deleting my tables and importing them again, twice in xlsx where I thought numbers will be numbers from the get-go, but that import even fails completely. I would rather not pay for an upgrade until I understand what is going on and why it is necessary.
I have also mixed feelings about going over the limit because of the created_at and updated_at columns, which cartodb creates automatically and does not let us delete…
Any thoughts on how to work around this? Any experience with this behavior?