Warner Chaves discusses improvements in columnstore indexes in SQL Server 2016:
SQL Server first introduced Columnar Storage with the SQL 2012 Enterprise release. In this release, Columnstores were read-only indexes, so it required to drop the index, load the table or partition and then rebuild the index to refresh it with the latest data.
SQL Server 2014 upgraded Columnstores with full read-write capabilities, allowing the Columnstore to become the ‘clustered’ index for the table and hold all the data instead of just being one more index on top of row-organized data. 2014 also introduced many improvements to batch operations so more pieces of an execution plan could take advantage of this faster processing mode.
Read on to see changes in 2016.