Monica Rathbun takes us through concepts behind columnstore indexes:
Now, I admit when these first were introduced in SQL Server 2012 I found them very intimidating (additionally, you couldn’t update them directly). For me, anytime you say columnstore, my mind tends to set off alarms saying wait stay away, this is too complicated. So, in this post I am going to try and simplify the feature for you.
To do that first you need to understand some terminology and the difference between a columnstore index and a row store index (the normal kind we all use). Let’s start with the terminology.
There are some interesting complications around columnstore indexes but for analytical or warehousing queries, they’re excellent.