cassandra: does it build index automatically with very high number of columns per row(Wide column)？

Question

I don't know wether there is a concept of wide columns now or not.

What is the definition of a wide column? How many columns in a wide column? What is the difference between cassandra and normal column and wide column processing? Will wide columns be automatically indexed?

I'm using datastax community edition of cassandra, version 3.11.3.

thanks!

Answer 1

Cassandra stores data as:

• slim row : Map[K, V]
• wide row : Map[K, Map[K, V]]

Slim row is usually referred to as entity per row while wide rows are entities clustered within one partition. If you think about the physical data layout as the map of maps then its easy to understand the query constraints of such model.