I installed MonetDB and imported a (uncompressed) 291 GB TSV MySQL dump. It worked like a charm and the database is really fast, but the database needs more than 542 GB on the disk. It seems like MonetDB is also able to use compression, but I was not able to find out how to enable (or even force) it. How can I do so? I don't know if it really speeds up execution, but I would like to try it.
There is no user-controllable compression scheme available in the official MonetDB release. The predominant compression scheme is dictionary encoding for string valued columns. In general, a compression scheme reduces the disk/network footprint by spending more CPU cycles.
To speed up queries, it might be better to first look at the TRACE of the SQL queries for simple hints on where the time is actually spent. This often give hints on 'liberal' use of column types. For example, a BIGINT is an overkill if the actual value range is known to fit in 32bits.