如何找到导致tempdb增长的SQL语句？

Question

服务器 (SQL Server 2008) 的 tempdb 每月数次增加到 500GB+。是否可以找出导致此问题的 SQL 语句？问题通常不是由create table #temp...; insert into #temp...或select ... into #temp...复杂的连接引起的。

某些 tempdb 文件的初始大小每次也会自动设置为更大的值。如何预防？

有时缓存的计划会阻止调整/缩小文件的大小。如何找到哪一个持有tempdb？

Answer 1

您可以使用三个 DMV 来跟踪 tempdb 的使用情况：

• sys.dm_db_task_space_usage
• sys.dm_db_session_space_usage
• sys.dm_db_file_space_usage

前两个将允许您在查询和会话级别跟踪分配。第三个跟踪跨版本存储、用户和内部对象的分配。

以下示例查询将为您提供每个会话的分配：

SELECT
  sys.dm_exec_sessions.session_id AS [SESSION ID]
  ,DB_NAME(database_id) AS [DATABASE Name]
  ,HOST_NAME AS [System Name]
  ,program_name AS [Program Name]
  ,login_name AS [USER Name]
  ,status
  ,cpu_time AS [CPU TIME (in milisec)]
  ,total_scheduled_time AS [Total Scheduled TIME (in milisec)]
  ,total_elapsed_time AS    [Elapsed TIME (in milisec)]
  ,(memory_usage * 8)      AS [Memory USAGE (in KB)]
  ,(user_objects_alloc_page_count * 8) AS [SPACE Allocated FOR USER Objects (in KB)]
  ,(user_objects_dealloc_page_count * 8) AS [SPACE Deallocated FOR USER Objects (in KB)]
  ,(internal_objects_alloc_page_count * 8) AS [SPACE Allocated FOR Internal Objects (in KB)]
  ,(internal_objects_dealloc_page_count * 8) AS [SPACE Deallocated FOR Internal Objects (in KB)]
  ,CASE is_user_process
             WHEN 1      THEN 'user session'
             WHEN 0      THEN 'system session'
  END         AS [SESSION Type], row_count AS [ROW COUNT]
FROM 
  sys.dm_db_session_space_usage
INNER join
  sys.dm_exec_sessions
ON  sys.dm_db_session_space_usage.session_id = sys.dm_exec_sessions.session_id

如果您想跟踪一段时间内的使用情况，请考虑使用sp_whoisactive收集数据，如Kendra Little 所示。