We should find out what database is using a lot of memory and if it's execution plans or the actual buffer pool. Have you set a max server memory setting for SQL Server? If not, you should.
Check out this query from this blog
-- Note: querying sys.dm_os_buffer_descriptors
-- requires the VIEW_SERVER_STATE permission.
DECLARE @total_buffer INT;
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
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;
This will break it down per database for you. Does a particular DB standout? Any of them using more ram than the actual DB size?
Then check out Glenn Barry's excellent blog for memory related queries such as this one. Post the results so we can see what is eating up your memory in SQL:
-- SQL Server 2008 and R2 Memory Related Queries
-- Glenn Berry
-- October 2010
-- http://glennberrysqlperformance.spaces.live.com/
-- Twitter: GlennAlanBerry
-- Instance Level queries
-- Good basic information about memory amounts and state (SQL 2008 and 2008 R2)
SELECT total_physical_memory_kb, available_physical_memory_kb,
total_page_file_kb, available_page_file_kb,
system_memory_state_desc
FROM sys.dm_os_sys_memory;
-- You want to see "Available physical memory is high"
-- SQL Server Process Address space info (SQL 2008 and 2008 R2)
--(shows whether locked pages is enabled, among other things)
SELECT physical_memory_in_use_kb,locked_page_allocations_kb,
page_fault_count, memory_utilization_percentage,
available_commit_limit_kb, process_physical_memory_low,
process_virtual_memory_low
FROM sys.dm_os_process_memory;
-- You want to see 0 for process_physical_memory_low
-- You want to see 0 for process_virtual_memory_low
-- Page Life Expectancy (PLE) value for default instance (SQL 2005, 2008 and 2008 R2)
SELECT cntr_value AS [Page Life Expectancy]
FROM sys.dm_os_performance_counters
WHERE OBJECT_NAME = N'SQLServer:Buffer Manager' -- Modify this if you have named instances
AND counter_name = N'Page life expectancy';
-- PLE is a good measurement of memory pressure.
-- Higher PLE is better. Below 300 is generally bad.
-- Watch the trend, not the absolute value.
-- Get total buffer usage by database for current instance (SQL 2005, 2008 and 2008 R2)
-- Note: This is a fairly expensive query
SELECT DB_NAME(database_id) AS [Database Name],
COUNT(*) * 8/1024.0 AS [Cached Size (MB)]
FROM sys.dm_os_buffer_descriptors
WHERE database_id > 4 -- system databases
AND database_id <> 32767 -- ResourceDB
GROUP BY DB_NAME(database_id)
ORDER BY [Cached Size (MB)] DESC;
-- Helps determine which databases are using the most memory on an instance
-- Memory Clerk Usage for instance
-- Look for high value for CACHESTORE_SQLCP (Ad-hoc query plans)
-- (SQL 2005, 2008 and 2008 R2)
SELECT TOP(20) [type], [name], SUM(single_pages_kb) AS [SPA Mem, Kb]
FROM sys.dm_os_memory_clerks
GROUP BY [type], [name]
ORDER BY SUM(single_pages_kb) DESC;
-- CACHESTORE_SQLCP SQL Plans These are cached SQL statements or batches that aren't in
-- stored procedures, functions and triggers
-- CACHESTORE_OBJCP Object Plans These are compiled plans for stored procedures,
-- functions and triggers
-- CACHESTORE_PHDR Algebrizer Trees An algebrizer tree is the parsed SQL text that
-- resolves the table and column names
-- Find single-use, ad-hoc queries that are bloating the plan cache
SELECT TOP(100) [text], cp.size_in_bytes
FROM sys.dm_exec_cached_plans AS cp
CROSS APPLY sys.dm_exec_sql_text(plan_handle)
WHERE cp.cacheobjtype = N'Compiled Plan'
AND cp.objtype = N'Adhoc'
AND cp.usecounts = 1
ORDER BY cp.size_in_bytes DESC;
-- Gives you the text and size of single-use ad-hoc queries that waste space in the plan cache
-- Enabling 'optimize for ad hoc workloads' for the instance can help (SQL Server 2008 and 2008 R2 only)
-- Enabling forced parameterization for the database can help, but test first!
-- Database level queries (switch to your database)
--USE YourDatabaseName;
--GO
-- Breaks down buffers used by current database by object (table, index) in the buffer cache
-- (SQL 2008 and 2008 R2) Note: This is a fairly expensive query
SELECT OBJECT_NAME(p.[object_id]) AS [ObjectName],
p.index_id, COUNT(*)/128 AS [Buffer size(MB)], COUNT(*) AS [BufferCount],
p.data_compression_desc AS [CompressionType]
FROM sys.allocation_units AS a
INNER JOIN sys.dm_os_buffer_descriptors AS b
ON a.allocation_unit_id = b.allocation_unit_id
INNER JOIN sys.partitions AS p
ON a.container_id = p.hobt_id
WHERE b.database_id = CONVERT(int,DB_ID())
AND p.[object_id] > 100
GROUP BY p.[object_id], p.index_id, p.data_compression_desc
ORDER BY [BufferCount] DESC;
-- Top Cached SPs By Total Logical Reads (SQL 2008 and 2008 R2). Logical reads relate to memory pressure
SELECT TOP(25) p.name AS [SP Name], qs.total_logical_reads AS [TotalLogicalReads],
qs.total_logical_reads/qs.execution_count AS [AvgLogicalReads],qs.execution_count,
ISNULL(qs.execution_count/DATEDIFF(Second, qs.cached_time, GETDATE()), 0) AS [Calls/Second],
qs.total_elapsed_time, qs.total_elapsed_time/qs.execution_count
AS [avg_elapsed_time], qs.cached_time
FROM sys.procedures AS p
INNER JOIN sys.dm_exec_procedure_stats AS qs
ON p.[object_id] = qs.[object_id]
WHERE qs.database_id = DB_ID()
ORDER BY qs.total_logical_reads DESC;
-- This helps you find the most expensive cached stored procedures from a memory perspective
-- You should look at this if you see signs of memory pressure
