I wrote a rough query to find the space in MB that DBs are using inside the buffer pool. The query is below:
SELECT ((count(*)*8192)/1048576) AS ‘MB in Buffer pool’
,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 1 DESC
Use the query below to find the percentage of memory an object is taking up.
SELECT sys.tables.name TableName,
sum(a.page_id)*8 AS MemorySpaceKB,
SUM(sys.allocation_units.data_pages)*8 AS StorageSpaceKB,
CASE WHEN SUM(sys.allocation_units.data_pages) <> 0 THEN
SUM(a.page_id)/CAST(SUM(sys.allocation_units.data_pages) AS NUMERIC(18,2))
END AS ‘Percentage Of Object In Memory’
FROM (SELECT database_id, allocation_unit_id, COUNT(page_id) page_id FROM
sys.dm_os_buffer_descriptors GROUP BY database_id, allocation_unit_id) a
JOIN sys.allocation_units ON a.allocation_unit_id =
sys.allocation_units.allocation_unit_id
JOIN sys.partitions ON (sys.allocation_units.type IN (1,3)
AND sys.allocation_units.container_id = sys.partitions.hobt_id)
OR (sys.allocation_units.type = 2 AND sys.allocation_units.container_id
= sys.partitions.partition_id)
JOIN sys.tables ON sys.partitions.object_id = sys.tables.object_id
AND sys.tables.is_ms_shipped = 0
WHERE a.database_id = DB_ID()
GROUP BY sys.tables.name
courtesy of http://searchsqlserver.techtarget.com/tip/0,289483,sid87_gci1334856,00.html
