sql server 正在运行的sql语句-阿里云开发者社区

开发者社区> 数据库> 正文
登录阅读全文

sql server 正在运行的sql语句

简介:

Introduction

sp_who2 is a well known utility that shows what spids are currently executing. However the information it shows is relatively limited. For example, it only shows the type of command executing as SELECT, DELETE etc, with no reference to the actual underlying SQL executing.

Knowing what SQL is executing can be vital in debugging why a query is taking a long time, or determining if it is being blocked. It can also be useful in showing the progress of a stored procedure i.e. what statement within the stored procedure is currently executing.

The utility described in this article will obviate these limitations of sp_who2.

The utility makes use of Dynamic Management Views (DMVs), so can be used by SQL Server 2005 or greater.

What SQL Statements Are Currently Executing Utility

The SQL used in this utility ‘dba_WhatSQLIsExecuting’ is given in Listing 1.

The Dynamic Management View (DMV) sys.db_exec_requests shows which requests are currently executing, the information shown includes the handle to the whole SQL text of the batch or stored procedure (sql_handle), together with offsets relating to the section of SQL within the batch that is currently executing (statement_start_offset and statement_end_offset).

To determine the current section of SQL currently executing, we need to call the Dynamic Management Function (DMF) sys.dm_exec_sql_text, passing in the handle of the SQL batch that is currently executing, and then apply the relevant offsets.

We can get more information about the query by combining the sys.db_exec_requests DMV with the sys.processes system view (joined on spid/session_id). This information includes who is executing the query, the machine they are running from, and the name of the database.

The utility selects relevant fields from the sys.db_exec_requests and sys.sysprocesses views. The selected fields are described in figure 1 (largely taken from SQL Server 2005 Books online).

Column name Data type Description
spid smallint SQL Server process ID.
ecid smallint Execution context ID used to uniquely identify the subthreads operating on behalf of a single process.
dbid smallint ID of the database currently being used by the process.
nt_username nchar(128) Windows user name for the process, if using Windows Authentication, or a trusted connection.
status nchar(30) Process ID status. For example, running and sleeping.
wait_type bigint Current wait time in milliseconds.
Individual Query varchar SQL Statement currently running.
Parent Query varchar Routine that contains the Individual Query.
program_name nchar(128) Name of the application program.
Hostname nchar(128) Name of the workstation.
nt_domain nchar(128) Microsoft Windows domain for the client, if using Windows Authentication, or a trusted connection.
Start_time datetime Time when the request is scheduled to run.

Figure 1 Columns in the ‘What SQL Statements Are Executing’ utility.

Running the utility on my SQL Server gives the results given in Figure 2.

Figure 2 Output from the ‘What SQL Statements Are Executing’ utility.

The results show the Parent Query that is running (typically a stored procedure), together with the Individual Query within the Parent Query that is currently executing. Additional useful information (e.g. database name, user name etc) is also shown.

Discussion

This utility allows you to observe the progress of a stored procedure or SQL batch, additionally it can be used to identify the cause of a long running query or blocking query.

Since the utility uses existing data held in DMVs it is relatively non-intrusive and should have little affect on performance.

If the identified queries are long running or causing blocking, it might be worthwhile running them inside the Database Tuning Advisor (DTA), this might identify the cause of the slow running (e.g. a missing index).

Further work

It is possible to extend this utility to report only on the database you are interested in, by providing a filter based on database name or database id.

It might be interesting to use the output to drive a trace and/or process-flow engine. This will report on process flow through a stored procedure, and could be useful in determining how much code has been hit/missed during testing, as well as getting a view on what code is executed for a given run/set of parameters.

Conclusion

The utility described in this article will allow you to identify what SQL statements are currently executing. This information can be useful in debugging the cause of both long running queries and blocking, and should prove valuable in the everyday work of the SQL Server DBA/developer.

Credits

Ian Stirkhas been working in IT as a developer, designer, and architect since 1987. He holds the following qualifications: M.Sc., MCSD.NET, MCDBA, and SCJP. He is a freelance consultant working with Microsoft technologies in London England. He can be contacted at Ian_Stirk@yahoo.com.

Code

复制代码

CREATE PROC [dbo].[dba_WhatSQLIsExecuting]
AS
/*--------------------------------------------------------------------
Purpose: Shows what individual SQL statements are currently executing.
----------------------------------------------------------------------
Parameters: None.
Revision History:
24/07/2008 Ian_Stirk@yahoo.com Initial version
Example Usage:
1. exec YourServerName.master.dbo.dba_WhatSQLIsExecuting
---------------------------------------------------------------------
*/
BEGIN
-- Do not lock anything, and do not get held up by any locks.
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED

-- What SQL Statements Are Currently Running?
SELECT [Spid] = session_Id
, ecid
,
[Database] = DB_NAME(sp.dbid)
,
[User] = nt_username
,
[Status] = er.status
,
[Wait] = wait_type
,
[Individual Query] = SUBSTRING (qt.text,
er.statement_start_offset
/2,
(
CASE WHEN er.statement_end_offset = -1
THEN LEN(CONVERT(NVARCHAR(MAX), qt.text)) * 2
ELSE er.statement_end_offset END -
er.statement_start_offset)
/2)
,
[Parent Query] = qt.text
, Program
= program_name
, Hostname
, nt_domain
, start_time
FROM sys.dm_exec_requests er
INNER JOIN sys.sysprocesses sp ON er.session_id = sp.spid
CROSS APPLY sys.dm_exec_sql_text(er.sql_handle)as qt
WHERE session_Id > 50 -- Ignore system spids.
AND session_Id NOT IN (@@SPID) -- Ignore this current statement.
ORDER BY 1, 2
END
复制代码
from http://www.sqlservercentral.com/articles/DMV/64425/
分类: MSSQL



    本文转自 Fanr_Zh 博客园博客,原文链接:http://www.cnblogs.com/Amaranthus/archive/2011/04/01/2002004.html,如需转载请自行联系原作者


版权声明:本文内容由阿里云实名注册用户自发贡献,版权归原作者所有,阿里云开发者社区不拥有其著作权,亦不承担相应法律责任。具体规则请查看《阿里云开发者社区用户服务协议》和《阿里云开发者社区知识产权保护指引》。如果您发现本社区中有涉嫌抄袭的内容,填写侵权投诉表单进行举报,一经查实,本社区将立刻删除涉嫌侵权内容。

分享:
数据库
使用钉钉扫一扫加入圈子
+ 订阅

分享数据库前沿,解构实战干货,推动数据库技术变革

其他文章