Columnstore index

From version SQL Server 2012, the database engine includes new types of indexes called columnstore indexes, which are in-memory structures that use compression technology to organize index data in a column-based format instead of the row-based format that traditional indexes use. Columnstore indexes are specifically designed to improve the performance of queries against data warehouse environments where you need to deal with large fact tables and related dimension tables. There are two types of columnstore indexes:

A non-clustered columnstore index is a read-only index that you can create on a table that has an existing standard clustered index, or on a table that is a heap. Like a standard non-clustered index, a non-clustered columnstore index can include one or more columns from the table.

A clustered columnstore index represents the actual data rows in the table, and is not a separate structure. This means that all columns are included in the index. Unlike non-clustered...