Columnstore Index is one of my favorite enhancement in SQL Server 2012. A columnstore index stores each column in a separate set of disk pages, rather than storing multiple rows per page as data traditionally has been stored. In case of the row store indexes multiple pages will contain multiple rows of the columns spanning across multiple pages. Whereas in case of column store indexes multiple pages will contain (multiple) single columns.  Columnstore Indexes are compressed by default and occupies much lesser space than regular row store index by default.

One of the very common question I often see is need of the list of columnstore index along with their size and corresponding table name. I quickly re-wrote a script using DMVs sys.indexes and sys.dm_db_partition_stats. This script gives the size of the columnstore index on disk only. I am sure there will be advanced script to retrieve details related to components associated with the columnstore index. However, I believe following script is sufficient to start getting an idea of columnstore index size. 

SELECT OBJECT_SCHEMA_NAME(i.OBJECT_ID) SchemaName,
OBJECT_NAME(i.OBJECT_ID ) TableName,
i.name IndexName,
SUM(s.used_page_count) / 128.0 IndexSizeinMB
FROM sys.indexes AS i
INNER JOIN sys.dm_db_partition_stats AS S
ON i.OBJECT_ID = S.OBJECT_ID AND I.index_id = S.index_id
WHERE  i.type_desc = 'NONCLUSTERED COLUMNSTORE'
GROUP BY i.OBJECT_ID, i.name

Here is my introductory article written on SQL Server Fundamentals of Columnstore Index. Create a sample columnstore index based on the script described in the earlier article. It will give the following results.

Please feel free to suggest improvement to script so I can further modify it to accommodate enhancements.

Reference: Pinal Dave (http://blog.sqlauthority.com)