Buffer Cache Usage Per Database

 

-- BUFFER CACHE USAGE PER DATABASE
SELECT COUNT(*)AS cached_pages_count  
    ,COUNT(*) / 128 / 1024 AS cached_GB  
    ,CASE database_id   
        WHEN 32767 THEN 'ResourceDb'   
        ELSE db_name(database_id)   
        END AS database_name  
FROM sys.dm_os_buffer_descriptors  
GROUP BY DB_NAME(database_id) ,database_id  
ORDER BY cached_pages_count DESC;