[DMV] Tempdb space

-- tempdb space

SELECT  SUM (user_object_reserved_page_count) * 8 AS user_objects_kb,

                           SUM (internal_object_reserved_page_count) * 8 AS internal_objects_kb,

                           SUM (version_store_reserved_page_count) * 8  AS version_store_kb,

                           SUM (unallocated_extent_page_count) * 8 AS freespace_kb

FROM     sys.dm_db_file_space_usage

WHERE   database_id = 2