Some time ago I've started the series of posts about immutability in data-oriented applications. One of approaches helping to deal with it was based on version flags. But fortunately it's not the only solution - especially for the ones who don't like to mix valid and invalid data in a single place.
The immutability is a precious property of systems dealing with a lot of data. It's especially true when something goes wrong and we must recover quickly. Since the data is immutable, the cleaning step is not executed and with some additional computation power, the data can be regenerated efficiently.
The interest of immutability in Big Data is often difficult to understand at the first glance. After all it introduces some complexity - especially at the reading path. But when the first problems appear and some of data need to be recomputed in order, the immutability comes to the rescue.
