This new DMV is basically a modified version of the DBCC IND command that is used to display the page allocations for a specific database object like a table. The advantage of the DMV is that it’s readily portable and provides a more complete picture of the allocations of the pages to the object it even display information about unallocated pages. Coupled with the use of dm_db_index_physical_stats and dm_db_partition_stats
It gives a very clear picture of what pages constitutes the table.
SELECT * FROM sys.Dm_db_database_page_allocations(DB_id(), object_id('pageAnalyzer'), NULL, 2, 'LIMITED')
There have been some know issues where the results from this DMV do not match with the results from DBCC IND. So DBCC IND still remains the preferred approach when identifying page counts and fragmentation.
Good read on Ghost records