Sql-Server
SQL Server 機器上的“正在使用”記憶體
我有一個具有 64GB RAM 的 SQL Server 2012 數據庫伺服器。一個名為 DataPumpService 的程序在同一個機器上執行,並從 2700 個平面文件中載入大約 4 億條記錄。
我想了解是什麼程序消耗了盒子上的所有物理記憶體,所以我轉到資源管理器(在任務管理器下):
從螢幕截圖中可以看出,In Use 記憶體約為 61GB,但兩個最佔用記憶體的程序的 Committed Bytes 和 Private Bytes 約為 3.3GB。
如何找出導致此伺服器上如此高的 In Use 記憶體的程序?
謝謝。
SQL Server 正在消耗所有這些記憶體。您看不到它正在消耗的記憶體,因為 SQL Server 可能正在使用不屬於伺服器工作集的“鎖定頁面”,而這通常是您在任務管理器中看到的所有內容。
在 MSDN 部落格之一上有詳細的說明。
我們應該找出哪個數據庫正在使用大量記憶體,以及它是執行計劃還是實際的緩衝池。您是否為 SQL Server 設置了最大伺服器記憶體設置?如果沒有,你應該。
從此部落格中查看此查詢
-- 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;
這將為您分解每個數據庫。特定的數據庫是否突出?他們中的任何一個使用比實際數據庫大小更多的記憶體嗎?
然後查看Glenn Barry 的優秀部落格,了解與記憶體相關的查詢,例如這個。發布結果,這樣我們就可以看到 SQL 中是什麼佔用了你的記憶體:
-- 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