text: -- percentage of buffer pool usage by db
  
  SELECT @total_buffer = cntr_value
     FROM sys.dm_os_performance_counters 
     WHERE RTRIM([object_name]) LIKE '%Buffer Manager'
     AND counter_name = 'Total Pages';
  
  WITH src AS
  (
     SELECT 
         database_id, db_buffer_pages = COUNT_BIG(*)
         FROM sys.dm_os_buffer_descriptors
         --WHERE database_id BETWEEN 5 AND 32766
         WHERE DB_NAME([database_id]) NOT IN ('master', 'model', 'msdb', 'distribution', 'tempdb') 
         GROUP BY database_id
  )
  SELECT
     [db_name] = CASE [database_id] WHEN 32767 
         THEN 'Resource DB' 
         ELSE DB_NAME([database_id]) END,
     db_buffer_pages,
     db_buffer_MB = db_buffer_pages / 128,
     db_buffer_percent = CONVERT(DECIMAL(6,3), 
         db_buffer_pages * 100.0 / @total_buffer)
  FROM src
  ORDER BY db_buffer_MB DESC;
  
  ------------------------------------------------------
  -- specific database
  
  WITH src AS
  (
     SELECT
         [Object] = o.name,
         [Type] = o.type_desc,
         [Index] = COALESCE(i.name, ''),
         [Index_Type] = i.type_desc,
         p.[object_id],
         p.index_id,
         au.allocation_unit_id
     FROM
         sys.partitions AS p
     INNER JOIN
         sys.allocation_units AS au
         ON p.hobt_id = au.container_id
     INNER JOIN
         sys.objects AS o
         ON p.[object_id] = o.[object_id]
     INNER JOIN
         sys.indexes AS i
         ON o.[object_id] = i.[object_id]
         AND p.index_id = i.index_id
     WHERE
         au.[type] IN (1,2,3)
         AND o.is_ms_shipped = 0
  )
  SELECT
     src.[Object],
     src.[Type],
     src.[Index],
     src.Index_Type,
     buffer_pages = COUNT_BIG(b.page_id),
     buffer_mb = COUNT_BIG(b.page_id) / 128
  FROM
     src
  INNER JOIN
     sys.dm_os_buffer_descriptors AS b
     ON src.allocation_unit_id = b.allocation_unit_id
  WHERE
     b.database_id = DB_ID()
  GROUP BY
     src.[Object],
     src.[Type],
     src.[Index],
     src.Index_Type
  ORDER BY
     buffer_pages DESC;
  