Microsoft® SQL Server 2012 Unleashed

Queries Using Columnstore Indexes

xVelocity columnstore indexes are a new feature in SQL Server 2012. An xVelocity memory-optimized columnstore index groups and stores data for each column in the table and then joins all the columns to complete the whole index. This type of index differs from traditional indexes, which group and store data for each row of data and then join all the rows to complete the whole index. For certain types of queries, such as data warehousing types of queries that access large amounts of data, the SQL Server query processor can take advantage of the columnstore index to significantly improve query execution times.

When the optimizer identifies a columnstore index and generates a query plan that makes use of the columnstore ...