Soldier: Damn Trekkies, always crashing the party pretending they’re time travelers.
Claudia: What a nerd.

— Warehouse 13 episode “Queen for a Day”

I was asked the question “What’s the point of a data warehouse if I have Hadoop”?  And if you know me – I tend to answer in terms of an analogy:

The best way to think about it is that a data warehouse (in the relational world) is like a Costco – lots of different stuff but still has a particular business domain (e.g. consumer goods from toilet paper for a year to laptops). While Hadoop is a the uber-warehouse – like a UPS warehouse which contains anything and everything. All of it is in pre-sized boxes (Hadoop breaks everything down into 64MB or 128MB chunks) and can be sent anywhere and everywhere.

Both are needed and important – they do similar things conceptually, yet do very different things implementation wise.