SQL Server 2016 introduced sys.dm_column_store_object_pool system view for finding the memory pool usage by different types of Columnstore Index objects.

I am sharing one T-SQL Script to find memory pool usage by Columnstore Indexes.
You can find one object_type column in the result set of below query.

The information of object_type column is:

1 = COLUMN_SEGMENT
2 = COLUMN_SEGMENT_PRIMARY_DICTIONARY
3 = COLUMN_SEGMENT_SECONDARY_DICTIONARY
4 = COLUMN_SEGMENT_BULKINSERT_DICTIONARY
5 = COLUMN_SEGMENT_DELETE_BITMAP

SELECT 
	OBJECT_NAME(csop.[object_id]) AS TableName
	,[i].[name] AS IndexName
	,[c].[name] AS ColumnName
	,[csop].[column_id]
	,[csop].[row_group_id]
	,[csop].[object_type_desc]
	,[csop].[access_count]
	,[csop].[memory_used_in_bytes]
	,[csop].[object_load_time]
FROM sys.dm_column_store_object_pool AS csop
LEFT OUTER JOIN sys.index_columns AS ic
	ON [ic].[index_column_id] = [csop].[column_id] 
		AND [ic].[index_id] = [csop].[index_id] 
		AND [ic].[object_id] = [csop].[object_id]
LEFT OUTER JOIN sys.columns AS c
	ON [ic].[object_id] = [c].[object_id] 
		AND [ic].[column_id] = [c].[column_id]
LEFT OUTER JOIN sys.indexes AS i
	ON [i].[object_id] = [csop].[object_id] 
		AND [i].[index_id] = [csop].[index_id]
ORDER BY [csop].[memory_used_in_bytes] DESC
GO