在C#和SQL Server Management Studio中的SQL查询非常不同的执行时间 [英] Very different execution times of SQL query in C# and SQL Server Management Studio
问题描述
我有一个简单的SQL查询,从C#中运行时,每次花费超过30秒,然后倍出,而当上的SQL Server Management Studio中运行成功完成瞬间。在后一种情况下,查询执行计划揭示什么麻烦,和执行时间为s $ P $垫很好通过几个简单的操作。
我已经运行 EXEC sp_who2
,而查询从C#中运行,它被列为考虑的CPU时间29000毫秒,并且没有被任何东西
我不知道如何开始解决这个。有没有人有一些见解?
查询是:
SELECT
c.lngId,
...
从tblCaseÇ
INNER JOIN tblCaseStatus S于s.lngId = c.lngId
INNER JOIN tblCaseStatusType T ON t.lngId = s.lngId
INNER JOIN [其他数据库] .. tblCompany厘米cm.lngId = cs.lngCompanyId
WHERE t.lngId = 25
和c.IsDeleted = 0
和s.lngStatus = 1
首先,从C#中运行时提取出查询的查询计划:
选择p.query_plan,*
从sys.dm_exec_requests视图 - [R
跨应用sys.dm_exec_query_plan(r.plan_handle)p
其中,r.session_id =< SPID C#连接的制造>
然后将其与SSMS会话下执行的计划比较(只需单击显示的工具栏在实际的计划)。
和,作为一般规则,总是试图应用系统的方法,而不是猜测。 等待和队列的是一个很好的,实践证明,解决性能问题的SQL Server的方法。
I have a simple SQL query that when run from C# takes over 30 seconds then times-out every time, whereas when run on SQL Server Management Studio successfully completes instantly. In the latter case, a query execution plan reveals nothing troubling, and the execution time is spread nicely through a few simple operations.
I've run 'EXEC sp_who2
' while the query is running from C#, and it is listed as taking 29,000 milliseconds of CPU time, and is not blocked by anything.
I have no idea how to begin solving this. Does anyone have some insight?
The query is:
SELECT
c.lngId,
...
FROM tblCase c
INNER JOIN tblCaseStatus s ON s.lngId = c.lngId
INNER JOIN tblCaseStatusType t ON t.lngId = s.lngId
INNER JOIN [Another Database]..tblCompany cm ON cm.lngId = cs.lngCompanyId
WHERE t.lngId = 25
AND c.IsDeleted = 0
AND s.lngStatus = 1
To start with, extract the query plan of the query when is run from C#:
select p.query_plan, *
from sys.dm_exec_requests r
cross apply sys.dm_exec_query_plan(r.plan_handle) p
where r.session_id = <spid of C# connection>
Then compare it with the plan executed under the SSMS session (simply click the Show actual plan in toolbar).
And, as a general rule, always try to apply a methodical approach rather than guess. Wait and Queues is a very good, proven, performance troubleshooting methodology for SQL Server.
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