Is Data Warehousing possible in MySQL and PostgresSQL
You can certainly use MySQL or PostgreSQL for this requirement using Python as your database access language. I've never used Python cubes so I can't speak to that. 

I would recommend that you use PostgreSQL - it has windowing functions and CTEs (common table expressions). It also supports CHECK CONSTRAINTs and a full range of set operators.


MySQL is reasonably good for read heavy OLTP database loads but
little else. 
PostgreSQL is superior for analytical work (DW - data warehousing, or
OLAP) while at the same time being an excellent all-rounder in the
OLTP arena.