Blocking

 

Blocking

user1 running a command on table1 which is still executing at the same time other user try to read/update the data from/to same table then user1 query will block the user2 Query.

 

 

 

 

Step1: Find the Blocking

There are number of ways to find out the details of the system processes IDs (spids) involved in blocking.

1.     sp_who2 System Stored Procedure

2.     sys.dm_exec_requests DMV

3.     sys.sysprocesses

4.     Sys.dm_os_waiting_tasks

5.     SQL Server Management Studio Activity Monitor

6.     SQL Server Management Studio Reports

7.     SQL Server Profiler

 

1.sp_who2 System Stored Procedure

The sp_who2 system stored procedure provides information about the current SQL Server processes with the associated SPID, status,login,Hostname,BlkBy,DBName,Command,CPU time, etc. The information returned can be filtered to return only the active processes by using the ‘active' parameter.

Below is some sample code and a screen shot with showing process 54 being blocked by process 53.

1.USE Master

Go

Sp_Who2

Go

 

2.USE Master

Go

Sp_Who2 active

Go

 

 

2.  sys.dm_exec_requests DMV

The sys.dm_exec_requests DMV provides details on all of the processes running in SQL Server. With the WHERE condition listed below, only blocked processes will be returned.

Use master

Go

select  * from sys.dm_exec_requests

where  blocking_session_id<>0

3. sys.sysprocesses

 

The sys.sysprocesses provides details on all of the processes running in SQL Server. With the WHERE condition listed below, only blocked processes will be returned.

Use master

GO

Select * from sys.sysprocesses where blocked<>0

 

4.sys.dm_os_waiting_tasks DMV

The sys.dm_os_waiting_tasks DMV returns information about the tasks that are waiting on resources.

USE Master

GO

SELECT session_id, wait_duration_ms, wait_type, blocking_session_id

FROM sys.dm_os_waiting_tasks

WHERE blocking_session_id <> 0

GO

5.SQL Server Management Studio Activity Monitor

It is easy procedure to do find the blocking from SSMS.

Open SSMS->Connect instance->Right click on instance-> select 'Activity Monitor'->Processes

OR

 

6.SQL Server Management Studio Reports

We can monitor the blocking on standard reports.

Open SSMS->Connect instance->Right click on instance->  Reports -> Standard Reports-> Activity - All Blocking Transactions.

 

7.SQL Server Profiler

To capture blocking related data on a continuous basis, one option is to run SQL Server Profiler and save the data to a table or file for analysis purposes. In order to configure Profiler to capture blocking related data, execute Profiler, configure the general properties. In addition, be sure to configure the 'blocked process threshold' before you start Profiler using this code:

sp_configure 'show advanced options', 1

GO

RECONFIGURE

GO

sp_configure 'blocked process threshold', 20

GO

RECONFIGURE

GO

Menu Bar->Tools->SQL Profiler->Connect the Instance->Select use template as TSQL-Lock->click on column filter->Select Database->Give the database name->ok->Run

 

Note: Don’t do this process in business hours. It causes a performance issue. Without change we can’t run the profiler.

  

 

Step2:INPUTBUFFER

Find the command which is running under SPID by using DBCCDBCC INPUTBUFFER(53)

Step3:KILL SPID

Kill the transaction by using below command

KILL 53

 

Note:

1.If select then kill the SPID ( Select command is not modify the data)

2. There is any other command part of the blocking then we can take the user/application team approval then we will kill it

 

Bandaru Ajeyudu

SQL and Azure DBA Trainer

Microsoft & Azure SQL DBA certified.

91-9494947541

Sqldbanow.com

ajeyudub@gmail.com                    

T-SQL query to get tables size in GB with no of rows in SQL server

Hi All,

Please find the below T-SQL script to get the tables size in GB with number of rows in SQL Server Database.

Use DB_Name;  --Change your database here

go

SELECT 

 s.name + '.' + t.Name AS [Table Name],

 part.rows AS [Total Rows In Table - Modified],

 CAST((SUM( DISTINCT au.Total_pages) * 8 ) / 1024.000 / 1024.000 AS NUMERIC(18, 3)) 

 AS [Table's Total Space In GB]

FROM 

 SYS.Tables t INNER JOIN sys.schemas s ON t.schema_id = s.schema_id

 INNER JOIN SYS.Indexes idx ON t.Object_id = idx.Object_id

 INNER JOIN SYS.Partitions part ON idx.Object_id = part.Object_id 

                    AND idx.Index_id = part.Index_id

 INNER JOIN SYS.Allocation_units au ON part.Partition_id = au.Container_id

 INNER JOIN SYS.Filegroups fGrp ON idx.Data_space_id = fGrp.Data_space_id

 INNER JOIN SYS.Database_files Df ON Df.Data_space_id = fGrp.Data_space_id

WHERE t.Is_ms_shipped = 0 AND idx.Object_id > 255 

GROUP BY t.Name, s.name, part.rows

ORDER BY [Table's Total Space In GB] DESC

Retrieve SSRS report schedule info through SQL

 --Retrieve SSRS report schedule info through SQL

Grabs information about what reports in SSRS are scheduled, when are they due to be sent out, 

report parameters and any errors in the last run etc.

Please note that the XPath on the [Parameters] column varies based on what parameters are setup in your own report. 

Please adjust them for your own purpose. Also the 'Prompt' value for a parameter is not stored, so you might have to 

join back to the relevant table for a friendly name.

Also there is additional info in the [ExtensionSetting].

=============================================================

  SELECT

[Locale],

[InactiveFlags],

'Next Run Date' = CASE next_run_date

WHEN 0 THEN null

ELSE

substring(convert(varchar(15),next_run_date),1,4) + '/' +

substring(convert(varchar(15),next_run_date),5,2) + '/' +

substring(convert(varchar(15),next_run_date),7,2)

END,

'Next Run Time' = isnull(CASE len(next_run_time)

WHEN 3 THEN cast('00:0'

+ Left(right(next_run_time,3),1)

+':' + right(next_run_time,2) as char (8))

WHEN 4 THEN cast('00:'

+ Left(right(next_run_time,4),2)

+':' + right(next_run_time,2) as char (8))

WHEN 5 THEN cast('0' + Left(right(next_run_time,5),1)

+':' + Left(right(next_run_time,4),2)

+':' + right(next_run_time,2) as char (8))

WHEN 6 THEN cast(Left(right(next_run_time,6),2)

+':' + Left(right(next_run_time,4),2)

+':' + right(next_run_time,2) as char (8))

END,'NA'),

Convert(XML,[ExtensionSettings]).value('(//ParameterValue/Value[../Name="TO"])[1]','nvarchar(50)') as [To]

,Convert(XML,[ExtensionSettings]).value('(//ParameterValue/Value[../Name="RenderFormat"])[1]','nvarchar(50)') as [Render Format]

,Convert(XML,[ExtensionSettings]).value('(//ParameterValue/Value[../Name="Subject"])[1]','nvarchar(50)') as [Subject]

        ---Example report parameters: StartDateMacro, EndDateMacro & Currency.

,Convert(XML,[Parameters]).value('(//ParameterValue/Value[../Name="StartDateMacro"])[1]','nvarchar(50)') as [Start Date]

,Convert(XML,[Parameters]).value('(//ParameterValue/Value[../Name="EndDateMacro"])[1]','nvarchar(50)') as [End Date]

,Convert(XML,[Parameters]).value('(//ParameterValue/Value[../Name="Currency"])[1]','nvarchar(50)') as [Currency]

,[ModifiedDate]

,S.[Description]

,[LastStatus]

,[EventType]

,[LastRunTime]

,[DeliveryExtension]

,[Version]

FROM [ReportServer$LIVE].[dbo].[Subscriptions] S

INNER JOIN ReportServer$LIVE.dbo.ReportSchedule R ON S.SubscriptionID = R.SubscriptionID

INNER JOIN msdb.dbo.sysjobs J ON Convert(nvarchar(128),R.ScheduleID) = J.name

INNER JOIN msdb.dbo.sysjobschedules JS ON J.job_id = JS.job_id

TempDB-Move TempDB Script in SQL Server

Hi All,

Please find the below mentioned script to generate the Move tempdb script in SQL Server 

 --Move_tempdb.sql

/*

Author: Brent Ozar

Original link: https://www.brentozar.com/archive/2017/11/move-tempdb-another-drive-folder/

*/

USE MASTER

GO

SELECT 'ALTER DATABASE tempdb MODIFY FILE (NAME = [' + f.name + '],'

    + ' FILENAME = ''Z:\MSSQL\DATA\' + f.name

    + CASE WHEN f.type = 1 THEN '.ldf' ELSE '.mdf' END

    + ''');'

FROM sys.master_files f

WHERE f.database_id = DB_ID(N'tempdb');

Notification --Email SP Results in SQL Server

 --Notification --Email SP Results

--https://www.sqlservercentral.com/scripts/email-sp-results

This piece of code will allow you to add a stored procedure name as a parameter, and will then take the output results of the procedure and email it to an address of your choosing, automatically formatting the results into an HTML table embedded in the email for clear and easy reading, or alternatively as an attachment.

Regretfully, there are a few limitations which I will eventually get around to fixing when I am interested in this again, namely:

Uses a static 100 length on the output columns instead of dynamically applying a length by referencing the source data

Cannot use procedures that have a blank column aliased ie.SELECT  ' ' as Store FROM table.

Requires Ad Hoc Distributed Queries server setting to be enabled.

Change cursors into tally or alternate loop

Customization of colours, table length, font etc.

It is executed as follows:

EXEC DBAdmin.[dbo].[dba_EmailProcResults] @vcProcName='sp_lock'

,@vcDatabaseName='master'

, @vcRecipients='<UrEmailHere>'

, @vcDynamicSubject = 'Log Backup Check'

=============================================================

 USE [tempdb]

GO

CREATE PROC [dbo].[dba_EmailProcResults]  --'dba_CheckLogbackups','DBAdmin', 'nicholaswilliams@', @vcDynamicSubject = 'Log Backup Check'

@vcProcName VARCHAR(1000)

,@vcDatabaseName VARCHAR(100)

,@vcRecipients VARCHAR(1000)

,@vcSchemaName VARCHAR(100) = NULL

,@bAttachQueryAsFile BIT = 0

,@vcDynamicSubject VARCHAR(100) = 'Query results'

AS

/*

sp_configure 'Show Advanced Options', 1

GO

RECONFIGURE

GO

sp_configure 'Ad Hoc Distributed Queries', 1

GO

RECONFIGURE

GO

*/

/*

Author: Nicholas Williams

Date: 20140519

Desc: Uses a proc as in input and email's the results.

Note: still plenty to update...

Procs cant reference non existant objects, even if logic would prevent them from being used ie. conditional if clause refering to non-existent table, as the remote call seems to force a parse on the query.

yet to make the table columns "smart" in terms of data lengths.

Requires Distributed Queries :/

add in a '?' reference help parameter

Cannot handle '' or blank string columns aliased as an actual column... need to fix.

@attach_query_result_as_file = 1,

    @query_attachment_filename='filename.csv',

*/

SET NOCOUNT ON

DECLARE

@vcServerName VARCHAR(100)

,@vcString VARCHAR(325)

,@vcColumnName VARCHAR(200)

,@nvcTable1 NVARCHAR(MAX)

,@nvcQuery NVARCHAR(MAX)

,@nvcBody NVARCHAR(MAX)

,@vcHeader VARCHAR(1000)

,@vcTrailer VARCHAR(1000)

DECLARE @MyTable TABLE

(

string NVARCHAR(MAX)

)

IF (@vcSchemaName) IS NULL

BEGIN

SET @vcSchemaName = 'dbo'

PRINT 'Warning: Schema name was null, setting it to dbo as a default.'

END

SET @vcServerName = 'Server='+(SELECT @@SERVERNAME)+';Trusted_Connection=yes;'

SELECT @vcString = 'EXEC ['+@vcDatabaseName+'].['+@vcSchemaName+'].'+(REPLACE(@vcProcName, '''',''''''))+''

EXEC ('

SELECT * INTO ##MyTempTable 

FROM OPENROWSET(''SQLNCLI'', '''+@vcServerName+''','''+@vcString+''')

')

IF (SELECT COUNT(1) FROM ##MyTempTable) >=1

BEGIN

IF @bAttachQueryAsFile <> 1

BEGIN

SET @vcHeader = '

<html><style>table{font-family:Arial;font-size:10;background=black;

color:Black;}html, body, title, 

head{font-family:Arial;font-size:10;background:white;color:Black;}th{font-family:Arial;font-size:15;background=orange;color:Black;}

{font-family:Arial;font-size:10;color:Black;background:White;align:left;valign:top;}</style><body><p><font face="Arial" size="2">Greetings,<br><br>Please see below.<br></font></p>'

SET @vcTrailer = '</body></html>'

--SELECT * FROM ##MyTempTable

SET @nvcTable1 = 

'<br>'+

'<table width=600 border=1 cellspacing=0 cellpadding=5>'+

'<tr style="background-color: White;">'

SET @nvcQuery = '

SELECT CAST((SELECT '

DECLARE column_cursor SCROLL CURSOR FOR

SELECT name FROM tempdb.sys.columns

WHERE object_id = 

(

SELECT id FROM tempdb.dbo.sysobjects

WHERE id = OBJECT_ID('tempdb..##MyTempTable')

)

/*

Need to put in a check to ensure that the result set is less than 4MB, so that it can be emailed.

*/

OPEN column_cursor

/*

Note: The odd use of the double fetch statement here is to force the force record of the fetch to be formatted differently, ie. no "," for the first record of the select.

hmm... now that I have changed how the select statement is used, i dont think i need it in the cursor anymore... change later.

*/

   FETCH FIRST FROM column_cursor

   INTO @vcColumnName

    SET @nvcQuery = ISNULL(@nvcQuery,'')+

'

['+@vcColumnName+'] AS ''td'','''''

SET @nvcTable1 = @nvcTable1 +

'<th width=100>'+@vcColumnName+'</th>'

   FETCH NEXT FROM column_cursor

   INTO @vcColumnName

WHILE @@FETCH_STATUS = 0

BEGIN 

SET @nvcTable1 = @nvcTable1 +

'<th width=100>'+@vcColumnName+'</th>'

SET @nvcQuery = ISNULL(@nvcQuery,'')+

'

,['+@vcColumnName+'] AS ''td'','''''

   FETCH NEXT FROM column_cursor

   INTO @vcColumnName

END

SET @nvcTable1 = @nvcTable1 +

'</tr>'

SET @nvcQuery = @nvcQuery+ 

'

FROM ##MyTempTable

FOR XML PATH(''tr''), TYPE) AS NVARCHAR(MAX))'

SET @vcTrailer= '</table><br><br><font face="Arial" size="2"><p>Regards</p><font face="Arial" size="2"><p>UrCompanyName<br></font><font size="1">Microsoft SQL Sever<br><br>Sender info:<br>'+'User - '+SYSTEM_USER+'<br>'+'Procedure - '+@vcProcName+'<br>'+'Database - '+@vcDatabaseName+'<br>'+'Server - '+isnull(@@SERVERNAME,'')+'<br></font></p>'

CLOSE column_cursor

DEALLOCATE column_cursor

INSERT INTO @MyTable

EXEC (@nvcQuery)

SELECT @nvcQuery = String FROM @MyTable

SELECT @nvcBody = @vcHeader+@nvcTable1+@nvcQuery+@vcTrailer

--SELECT @nvcBody

EXEC msdb.dbo.sp_send_dbmail   

@recipients = @vcRecipients

,@subject = @vcDynamicSubject

,@body = @nvcBody

,@body_format = 'HTML'  

END

ELSE

BEGIN

EXEC msdb.dbo.sp_send_dbmail   

@recipients = @vcRecipients

,@subject = @vcDynamicSubject

,@body = 'Please View attached file for query results.'

,@body_format = 'Text' 

,@attach_query_result_as_file = 1

,@query_attachment_filename = 'QueryResults.xls'

,@query_result_separator = ' '

,@query_result_no_padding = 0

,@query = 'SET NOCOUNT ON SELECT * FROM ##MyTempTable SET NOCOUNT OFF'

END

END

DROP TABLE ##MyTempTable

SET NOCOUNT OFF

/*

set a variable for the table width and the column widths.

add to each length for table for each iteration of the cursor.

look at sys.columns table for data type of the columns to manage table size effectively.

-- td = tranDate,''''

*/

SET NOCOUNT OFF