获取花费超过数小时的查询的实际执行计划？

Question

在执行分析时观察到特定过程在 SQL VM 上 运行 需要 10 分钟，但由于某种原因，它在 SQL 托管实例中需要 1 分钟。这发生在生产环境中。

进一步分析试图获得实际的执行计划，并且执行时间更长，比如超过 30 分钟，但没有完成。 有谁知道为什么执行需要很长时间？

Answer 1

@VikrantMore，这里是检查正在使用 tempdb 的查询及其执行计划的查询。看到这可以帮助你。

SELECT
t1.session_id
, t1.request_id
, task_alloc_GB = CAST((t1.task_alloc_pages * 8./1024./1024.) AS NUMERIC(10,1))
, task_dealloc_GB = CAST((t1.task_dealloc_pages * 8./1024./1024.) AS NUMERIC(10,1))
, host= CASE WHEN t1.session_id <= 50 then 'SYS' else s1.host_name end
, s1.login_name
, s1.status
, s1.last_request_start_time
, s1.last_request_end_time
, s1.row_count
, s1.transaction_isolation_level
, query_text=
    COALESCE((SELECT SUBSTRING(text, t2.statement_start_offset/2 + 1,
      (CASE WHEN statement_end_offset = -1
          THEN LEN(CONVERT(nvarchar(MAX),text)) * 2
               ELSE statement_end_offset
          END - t2.statement_start_offset)/2)
    FROM sys.dm_exec_sql_text(t2.sql_handle)) , 'Not currently executing')
, query_plan=(SELECT query_plan FROM sys.dm_exec_query_plan(t2.plan_handle))
FROM
(SELECT session_id, request_id
, task_alloc_pages=SUM(internal_objects_alloc_page_count +   
user_objects_alloc_page_count)
, task_dealloc_pages = SUM (internal_objects_dealloc_page_count + 
user_objects_dealloc_page_count)
FROM sys.dm_db_task_space_usage
GROUP BY session_id, request_id) AS t1
LEFT JOIN sys.dm_exec_requests AS t2 ON
t1.session_id = t2.session_id
and t1.request_id = t2.request_id
LEFT JOIN sys.dm_exec_sessions AS s1 ON
t1.session_id=s1.session_id
WHERE
t1.session_id > 50 -- ignore system unless you suspect there's a problem there
and t1.session_id <> @@SPID -- ignore this request itself
ORDER BY t1.task_alloc_pages DESC;
GO