I am trying to use a stored procedure in the OLE DB source, I am using the SQL Command for the Data Access mode. It returns values when using the preview but when I test the SSIS package I receive the error, "A rowset based on the SQL command was not returned by the OLE DB provider
Solution
I just had to add SET NOCOUNT ON in the begining of the stored procedure that I was using.
This blog is created to add all the information and experiences that I have learnt while working on MS sql server as a DBA. The blog is also updated frequently with the real world problem that I encounter hands on at work and the resolutions to resolve them. I hope this blog will be of some use to you and you will revisit. Thank you for stopping by and you are welcome to leave comments.
Wednesday, December 21, 2011
Thursday, October 27, 2011
Replacing multiple occurences of space with one space in a string
Given string : THIS IS A BAD STRING
Out put string : THIS IS A BAD STRING
The Logic
-----------------
@str AS VARCHAR(1000) = 'THIS IS A BAD STRING',@Token AS VARCHAR(1) = '~'
SELECT REPLACE(REPLACE(REPLACE(@str,' ','~ '),' ~',''),'~',' ')
Out put string : THIS IS A BAD STRING
The Logic
-----------------
- In the given string replcae the space with a token (e,g. ~ in this case) and a space e.g. '~ '
- Repace the space and token in the string result from step 1 with an empty string.' ~'
- Replace the result of the above atring with a token and the space
@str AS VARCHAR(1000) = 'THIS IS A BAD STRING',@Token AS VARCHAR(1) = '~'
SELECT REPLACE(REPLACE(REPLACE(@str,' ','~ '),' ~',''),'~',' ')
Counting the occurence of a substring within a string
Today I learnt a special techinque from SQL Server magazine to find the total number of substrings within a string. The logic is so simple that I am surprised why I never used it.
E.g. abcdballmnopballqrstball
We need to find the total number of occurences of the substring "ball" in the given string.
Logic
--------------
Find the substring ball and replace it with '' e.g.abcdmnopqrst
Find the length of the new string 12
Subtract the new length from the lenth of the original string 24-12 = 12
Divide the new number with the length of the substring 12/4 = 3
Here is the script - taken form the November issue of SQL server magazine
DECLARE
@str AS VARCHAR(1000) = ' abcdballmnopballqrstball ';
@substr AS VARCHAR(1000) = 'ball';
SELECT LEN(@str) - LEN(REPLACE(@str,(@substr,''>/LEN(@substr)
This is so awesome!
E.g. abcdballmnopballqrstball
We need to find the total number of occurences of the substring "ball" in the given string.
Logic
--------------
Find the substring ball and replace it with '' e.g.abcdmnopqrst
Find the length of the new string 12
Subtract the new length from the lenth of the original string 24-12 = 12
Divide the new number with the length of the substring 12/4 = 3
Here is the script - taken form the November issue of SQL server magazine
DECLARE
@str AS VARCHAR(1000) = ' abcdballmnopballqrstball ';
@substr AS VARCHAR(1000) = 'ball';
SELECT LEN(@str) - LEN(REPLACE(@str,(@substr,''>/LEN(@substr)
This is so awesome!
Friday, October 14, 2011
COALESCE - Selecting each record with all not nul values
I had three rows of data that had the same acount number but differnt variation in the three columns. I had to select each account with not null column . This was achieved by the following...
My data
create table #tmpcol(c219 int, c220 int,c221 int)
INSERT INTO #tmpcol
SELECT null,220,null
INSERT INTO #tmpcol
SELECT 219,null,null
INSERT INTO #tmpcol
SELECT null,null,221
select top 1 * from #tmpcolorderby coalesce(100*c219,10*c220,c221) desc
My data
create table #tmpcol(c219 int, c220 int,c221 int)
INSERT INTO #tmpcol
SELECT null,220,null
INSERT INTO #tmpcol
SELECT 219,null,null
INSERT INTO #tmpcol
SELECT null,null,221
select top 1 * from #tmpcolorderby coalesce(100*c219,10*c220,c221) desc
Friday, September 16, 2011
Shrink the transaction log file
The steps needed to shrink the transaction log file
Scenario: The database is in FULL RECOVERY mode and the transaction log file was growing to more than 2GB. We were taking the transaction logbackups in every 1 hour inteval. However the transaction log file still grew because at one point someone just set the recovery mode to FULL and there was no transaction log backups set up. The following steps were taken to reduce the siz of the log file.
--check the log file name
select * from sys.database_files
--Truncate the log by changing the database recovery model to SIMPLE. ( checkpoint occurs-frees up VLFs)
ALTER DATABASE ARCHIVEhcfsdatabase
SET RECOVERY SIMPLE;
GO
-- Shrink the truncated log file the smalles size possible
DBCC SHRINKFILE (ARCHIVEhcfsdatabase_Log,0, TRUNCATEONLY);
GO
--reset the log file size to 64MB
ALTER DATABASE archivehcfsdatabase
Modify FIle(Name = 'ARCHIVEhcfsdatabase_Log',
,Size = 1024
)
-- Reset the database recovery model.
ALTER DATABASE ARCHIVEhcfsdatabase
SET RECOVERY FULL;
GO
--Do a full Back up - Until a full back up is done the database is not set to full recovery mode--
Scenario: The database is in FULL RECOVERY mode and the transaction log file was growing to more than 2GB. We were taking the transaction logbackups in every 1 hour inteval. However the transaction log file still grew because at one point someone just set the recovery mode to FULL and there was no transaction log backups set up. The following steps were taken to reduce the siz of the log file.
--check the log file name
select * from sys.database_files
--Truncate the log by changing the database recovery model to SIMPLE. ( checkpoint occurs-frees up VLFs)
ALTER DATABASE ARCHIVEhcfsdatabase
SET RECOVERY SIMPLE;
GO
-- Shrink the truncated log file the smalles size possible
DBCC SHRINKFILE (ARCHIVEhcfsdatabase_Log,0, TRUNCATEONLY);
GO
--reset the log file size to 64MB
ALTER DATABASE archivehcfsdatabase
Modify FIle(Name = 'ARCHIVEhcfsdatabase_Log',
,Size = 1024
)
-- Reset the database recovery model.
ALTER DATABASE ARCHIVEhcfsdatabase
SET RECOVERY FULL;
GO
--Do a full Back up - Until a full back up is done the database is not set to full recovery mode--
Monday, August 15, 2011
Drop a database
1. You have to be in the master database.
2. Take the database to the single user mode.
3. Drop the database.
use master;GO
alter database [databaseName]
set single_user with rollback immediate;
drop database [databaseName];
2. Take the database to the single user mode.
3. Drop the database.
use master;GO
alter database [databaseName]
set single_user with rollback immediate;
drop database [databaseName];
Wednesday, August 3, 2011
Creating a XML file from SQL data using VB.net
The project involved creating a xml file in the following format with the data from the SQLserver 2008 tables.
File Sample
<claimTrackingRequest>
<Target>
<identifier>1015100236</identifier>
<Type>RCV</Type>
<Comment>
<Code />
<Text>07/29 - comment test1 </Text>
</Comment>
</Target>
<Target>
<identifier>1015700095</identifier>
<Type>RCV</Type>
<Comment>
<Code />
<Text>07/25 - comment test1</Text>
</Comment>
<Comment>
<Code />
<Text>07/26 - comment test2 </Text>
</Comment>
<Comment>
<Code />
<Text>07/26 - comment test2 </Text>
</Comment>
</Target>
</claimTrackingRequest>
The above result was returned by the stored proc PROC_NOTES_STATUSCHANGENOTES_BY_HOSCODE_SELECT_CNA_newformat
( The stored procedure details is listed at the end of the post)
I am using VB.NET to write the result returned by the stored proc to a file with extension XML
I am using a DATASET to pull the result and then using the STREAMWRITER to writer the dataset result to the file.
Sub Main()
Dim sqlConn As New SqlConnection
sqlConn.ConnectionString = "Data Source=sqlsvr1;Initial Catalog=db01;Integrated Security=SSPI;"Dim sqlCmd As New SqlCommandsqlCmd.CommandText = "PROC_NOTES_STATUSCHANGENOTES_BY_HOSCODE_SELECT_CNA_newformat"sqlCmd.CommandType = CommandType.StoredProcedure
sqlCmd.Connection = sqlConn
sqlCmd.CommandTimeout = 120
sqlCmd.Parameters.Add("@DTBEGIN", SqlDbType.Date).Value = "07/26/2011"sqlCmd.Parameters.Add("@DTEND", SqlDbType.Date).Value = "07/29/2011"Dim ds As New DataSetTrysqlConn.Open()
Dim a As System.Data.SqlClient.SqlDataAdaptera = New SqlDataAdapter(sqlCmd)
a.Fill(ds)
sqlConn.Close()
Using writer As StreamWriter = New StreamWriter("c:\test\notes.xml", True)
writer.Flush()
For Each _row As DataRow In ds.Tables(0).Rows
writer.Write(_row.Item(0).ToString())
Nextwriter.Close()
End Using
Catch ex As ExceptionEnd Try
End Sub
/*The stored proc returning the XML result is as follows */
--The proc is using XML Query
USE [db01]GO/****** Object: StoredProcedure [dbo].[PROC_NOTES_STATUSCHANGENOTES_BY_HOSCODE_SELECT_CNA_newformat] Script Date: 08/03/2011 12:48:43 ******/SET
GO
SET
GO
CREATE ANSI_NULLS ON QUOTED_IDENTIFIER ON PROCEDURE [dbo].[PROC_NOTES_STATUSCHANGENOTES_BY_HOSCODE_SELECT_CNA_newformat] (@DTBEGIN SMALLDATETIME, @DTEND SMALLDATETIME)AS/*turn these off so that it wont error if it trys to divide by Zero when doing calcs*/SET
SETARITHABORT OFF ANSI_WARNINGS OFF/*Create a temp table*/CREATE TABLE #TEMPTBLCNA (
RECORD_NUM
C1 INT NULL, VARCHAR(1) NULL,COMMENT_CODE VARCHAR(100) NULL,STATUS_CODE INT NULL,STATUS_DESC VARCHAR(200) NULL,COMMENT VARCHAR(1500) NULL,ACCOUNT VARCHAR(12) NULL,HOSPITAL INT NULL,DATEENTERED DATETIME NULL,PTNO INT NULL,NOTEID INT IDENTITY(1,1) )/*GET 100's*/INSERT INTO #TEMPTBLCNA (RECORD_NUM, C1,COMMENT_CODE,STATUS_CODE,STATUS_DESC,COMMENT,ACCOUNT,HOSPITAL,DATEENTERED,PTNO)SELECTMIN(C.RECORD_NUM), LEFT(COMMENT_CODE,1),C.COMMENT_CODE,LEFT(C.COMMENT_CODE, 3),m.[STATUS],c.COMMENT,RIGHT(DBO.STRIP_NONNUMERIC_12(P.ACCOUNT), 12),p.HOSPITAL, CAST(CONVERT(VARCHAR(10),C.DATEENTERED,101) AS DATETIME),P.PTNOFROMCOMMENTS C INNER JOIN PATIENT_TABLE P ON C.PTNO = P.PTNOINNER JOIN MasterCodeList mON m.NewCode = LEFT(C.COMMENT_CODE, 3)
WHERE CAST(CONVERT(VARCHAR,C.DATEENTERED,101) AS DATETIME) BETWEEN '07/22/2011' AND '07/29/2011'
GROUP BY P.PTNO,P.ACCOUNT,C.Comment,C.COMMENT_CODE,p.HOSPITAL,C.DATEENTERED,LEFT(COMMENT_CODE,1),m.[status]ORDERBY P.PTNO--select * from #TEMPTBLCNASELECT
( c.ACCOUNT as 'identifier', 'RCV' as 'Type', SELECT '' AS 'Code',a.comment AS 'Text'
FROM #TEMPTBLCNA aWHERE a.ptno = c.ptnoFOR XML PATH(''), TYPE) AS 'Comment'
FROM #TEMPTBLCNA cgroup by c.ptno,c.ACCOUNTFOR XML PATH('Target'), ROOT('claimTrackingRequest')
DROP TABLE #TEMPTBLCNASET
SET ARITHABORT ON ANSI_WARNINGS ON
File Sample
<claimTrackingRequest>
<Target>
<identifier>1015100236</identifier>
<Type>RCV</Type>
<Comment>
<Code />
<Text>07/29 - comment test1 </Text>
</Comment>
</Target>
<Target>
<identifier>1015700095</identifier>
<Type>RCV</Type>
<Comment>
<Code />
<Text>07/25 - comment test1</Text>
</Comment>
<Comment>
<Code />
<Text>07/26 - comment test2 </Text>
</Comment>
<Comment>
<Code />
<Text>07/26 - comment test2 </Text>
</Comment>
</Target>
</claimTrackingRequest>
The above result was returned by the stored proc PROC_NOTES_STATUSCHANGENOTES_BY_HOSCODE_SELECT_CNA_newformat
( The stored procedure details is listed at the end of the post)
I am using VB.NET to write the result returned by the stored proc to a file with extension XML
I am using a DATASET to pull the result and then using the STREAMWRITER to writer the dataset result to the file.
Sub Main()
Dim sqlConn As New SqlConnection
sqlConn.ConnectionString = "Data Source=sqlsvr1;Initial Catalog=db01;Integrated Security=SSPI;"Dim sqlCmd As New SqlCommandsqlCmd.CommandText = "PROC_NOTES_STATUSCHANGENOTES_BY_HOSCODE_SELECT_CNA_newformat"sqlCmd.CommandType = CommandType.StoredProcedure
sqlCmd.Connection = sqlConn
sqlCmd.CommandTimeout = 120
sqlCmd.Parameters.Add("@DTBEGIN", SqlDbType.Date).Value = "07/26/2011"sqlCmd.Parameters.Add("@DTEND", SqlDbType.Date).Value = "07/29/2011"Dim ds As New DataSetTrysqlConn.Open()
Dim a As System.Data.SqlClient.SqlDataAdaptera = New SqlDataAdapter(sqlCmd)
a.Fill(ds)
sqlConn.Close()
Using writer As StreamWriter = New StreamWriter("c:\test\notes.xml", True)
writer.Flush()
For Each _row As DataRow In ds.Tables(0).Rows
writer.Write(_row.Item(0).ToString())
Nextwriter.Close()
End Using
Catch ex As ExceptionEnd Try
End Sub
/*The stored proc returning the XML result is as follows */
--The proc is using XML Query
USE [db01]GO/****** Object: StoredProcedure [dbo].[PROC_NOTES_STATUSCHANGENOTES_BY_HOSCODE_SELECT_CNA_newformat] Script Date: 08/03/2011 12:48:43 ******/SET
GO
SET
GO
CREATE ANSI_NULLS ON QUOTED_IDENTIFIER ON PROCEDURE [dbo].[PROC_NOTES_STATUSCHANGENOTES_BY_HOSCODE_SELECT_CNA_newformat] (@DTBEGIN SMALLDATETIME, @DTEND SMALLDATETIME)AS/*turn these off so that it wont error if it trys to divide by Zero when doing calcs*/SET
SETARITHABORT OFF ANSI_WARNINGS OFF/*Create a temp table*/CREATE TABLE #TEMPTBLCNA (
RECORD_NUM
C1 INT NULL, VARCHAR(1) NULL,COMMENT_CODE VARCHAR(100) NULL,STATUS_CODE INT NULL,STATUS_DESC VARCHAR(200) NULL,COMMENT VARCHAR(1500) NULL,ACCOUNT VARCHAR(12) NULL,HOSPITAL INT NULL,DATEENTERED DATETIME NULL,PTNO INT NULL,NOTEID INT IDENTITY(1,1) )/*GET 100's*/INSERT INTO #TEMPTBLCNA (RECORD_NUM, C1,COMMENT_CODE,STATUS_CODE,STATUS_DESC,COMMENT,ACCOUNT,HOSPITAL,DATEENTERED,PTNO)SELECTMIN(C.RECORD_NUM), LEFT(COMMENT_CODE,1),C.COMMENT_CODE,LEFT(C.COMMENT_CODE, 3),m.[STATUS],c.COMMENT,RIGHT(DBO.STRIP_NONNUMERIC_12(P.ACCOUNT), 12),p.HOSPITAL, CAST(CONVERT(VARCHAR(10),C.DATEENTERED,101) AS DATETIME),P.PTNOFROMCOMMENTS C INNER JOIN PATIENT_TABLE P ON C.PTNO = P.PTNOINNER JOIN MasterCodeList mON m.NewCode = LEFT(C.COMMENT_CODE, 3)
WHERE CAST(CONVERT(VARCHAR,C.DATEENTERED,101) AS DATETIME) BETWEEN '07/22/2011' AND '07/29/2011'
GROUP BY P.PTNO,P.ACCOUNT,C.Comment,C.COMMENT_CODE,p.HOSPITAL,C.DATEENTERED,LEFT(COMMENT_CODE,1),m.[status]ORDERBY P.PTNO--select * from #TEMPTBLCNASELECT
( c.ACCOUNT as 'identifier', 'RCV' as 'Type', SELECT '' AS 'Code',a.comment AS 'Text'
FROM #TEMPTBLCNA aWHERE a.ptno = c.ptnoFOR XML PATH(''), TYPE) AS 'Comment'
FROM #TEMPTBLCNA cgroup by c.ptno,c.ACCOUNTFOR XML PATH('Target'), ROOT('claimTrackingRequest')
DROP TABLE #TEMPTBLCNASET
SET ARITHABORT ON ANSI_WARNINGS ON
Thursday, July 14, 2011
Searching for a string in the filename and moving, renaming it using SSIS
I had to create a project ot navigate through a folder and look for a file that has EXE string in the file name ( not as the extension) of the file. e.g. NormanEXE1234.txt. Then once the file was found it had to be copied to the archive folder and the origianl file ahd to be reamed as hcfsnorman.txt.
After almost two days of trying to figure out how to do it, I have completed the task successfully. There were not much write up on this on the internet to my suprise. I could find tutorials only on coppying and moving of the file but not searching for a particular string to match in the filename. Finally, I thought I would put this steps together and here it is....
The following screen( on the left of the screen) shows the different variables declaration. The control flow has two file system task One for archiving the files and the other for renaming the original file.Both the tasks are encapsulated in a For each loop container as we will be navigating through all the files in the folder to find the match for the files we want to move to the archive folder.
The variables userd:
Double click on the For each loop container and fill up as follows. The filespec property of the expression of the container should be the filename since we will be searching for the filenames that has EXE string in it.
Double click the FileSystem Task editor and change the destination path variable, the source connection and the operation. The source connection called ExtendedServices is a flat file connection.
The flat file connection is created as follows where in file name we have file://sanftps/FTPUsers/354norman/ToHCFS/*EXE*.txt
Next, the most important part of the project is to define building the expression for the connection string of the file connection to look for a certain string ( EXE - in this case) in the source folder.
Click on the (..) next to the expression in the proeprty page of the connection manager.
Select the property Conenction string and then click on the expression to open up a screen as shown in the picture below.
This is where we specify the expression for the connection string.
FINDSTRING( @[User::vFileSourcePath] + @[User::vFileName] , @[User::vFileSpec] ,1) > 0? @[User::vFileSourcePath] + @[User::vFileName] :""
Basically, we are using FINDSTRING string function and tying it to the Boolean Operand to build the connection string. That's all.
After almost two days of trying to figure out how to do it, I have completed the task successfully. There were not much write up on this on the internet to my suprise. I could find tutorials only on coppying and moving of the file but not searching for a particular string to match in the filename. Finally, I thought I would put this steps together and here it is....
The following screen( on the left of the screen) shows the different variables declaration. The control flow has two file system task One for archiving the files and the other for renaming the original file.Both the tasks are encapsulated in a For each loop container as we will be navigating through all the files in the folder to find the match for the files we want to move to the archive folder.
The variables userd:
- vArchiveFile : Stores the path where the file will be moved to archive ( destination folder)
- vFileName : Name of the file ( source fie name)
- vFileSourcePath : The path of the original file where it is found
- vFilsSpec : The string to search in the filename
- vWorkingFileName : The name of the file to be renamed
Double click on the For each loop container and fill up as follows. The filespec property of the expression of the container should be the filename since we will be searching for the filenames that has EXE string in it.
Double click the FileSystem Task editor and change the destination path variable, the source connection and the operation. The source connection called ExtendedServices is a flat file connection.
The flat file connection is created as follows where in file name we have file://sanftps/FTPUsers/354norman/ToHCFS/*EXE*.txt
Next, the most important part of the project is to define building the expression for the connection string of the file connection to look for a certain string ( EXE - in this case) in the source folder.
Click on the (..) next to the expression in the proeprty page of the connection manager.
Select the property Conenction string and then click on the expression to open up a screen as shown in the picture below.
This is where we specify the expression for the connection string.
FINDSTRING( @[User::vFileSourcePath] + @[User::vFileName] , @[User::vFileSpec] ,1) > 0? @[User::vFileSourcePath] + @[User::vFileName] :""
Basically, we are using FINDSTRING string function and tying it to the Boolean Operand to build the connection string. That's all.
Monday, June 27, 2011
Error:System.Data.SqlClient.SqlException: profile name is not valid
We were getting the following error
@profile_name = 'profile1@abc.com'
@principal_name = 'public',@is_default = 1;
Once we did the above two setps after creating the profile the error was gone and everything started to work as normal.=
System.Data.SqlClient.SqlException: profile name is not valid
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
The profile name is profile1@abc.com
user account associated to it was accountA@abc.com
We had to do the following to get rid of this error
Make sure that the account accountA@abc.com is a role member of the Role DataBaseMailUserRole in the msdb database.This role is found under Security->Role in the msdb database
Set the profile profile1@abc.com to public
use msdb
GO
EXECUTE msdb.dbo.sysmail_add_principalprofile_sp@profile_name = 'profile1@abc.com'
@principal_name = 'public',@is_default = 1;
Once we did the above two setps after creating the profile the error was gone and everything started to work as normal.=
Friday, June 24, 2011
Find missing indexes
--missing indexes on a single table
SELECT user_seeks * avg_total_user_cost * ( avg_user_impact * 0.01 )AS [index_advantage] ,migs.last_user_seek ,mid.[statement] AS [Database.Schema.Table] ,mid.equality_columns ,mid.inequality_columns ,mid.included_columns ,migs.unique_compiles ,migs.user_seeks ,migs.avg_total_user_cost ,migs.avg_user_impactFROM sys.dm_db_missing_index_group_stats AS migs WITH ( NOLOCK )INNER JOIN sys.dm_db_missing_index_groups AS mig WITH ( NOLOCK )
ON migs.group_handle = mig.index_group_handleINNER JOIN sys.dm_db_missing_index_details AS mid WITH ( NOLOCK )ON mig.index_handle = mid.index_handleWHERE
AND mid.database_id = DB_ID() mid.[statement]= '[statusupdates].[dbo].[Referrals]'ORDER
Look at the last_user_seek column and see how frequently it is seeked. This is an important factor to decide whether the suggested index is needed or not
I created the following index based on the equality column and there was no include column NONCLUSTERED INDEX IDX_referrals_Account
CREATE
ON Referrals (Account,Hospitalcode,Deleted,uploaded )
GO
/* to see when was the last index was updated*/
DBCC SHOW_STATISTICS ('referrals', 'IDX_referrals_hospitalcode') GO
/* after adding the new index I updated the statistics of the table */
EXEC
GO sp_updatestats
GO
SELECT user_seeks * avg_total_user_cost * ( avg_user_impact * 0.01 )AS [index_advantage] ,migs.last_user_seek ,mid.[statement] AS [Database.Schema.Table] ,mid.equality_columns ,mid.inequality_columns ,mid.included_columns ,migs.unique_compiles ,migs.user_seeks ,migs.avg_total_user_cost ,migs.avg_user_impactFROM sys.dm_db_missing_index_group_stats AS migs WITH ( NOLOCK )INNER JOIN sys.dm_db_missing_index_groups AS mig WITH ( NOLOCK )
ON migs.group_handle = mig.index_group_handleINNER JOIN sys.dm_db_missing_index_details AS mid WITH ( NOLOCK )ON mig.index_handle = mid.index_handleWHERE
AND mid.database_id = DB_ID() mid.[statement]= '[statusupdates].[dbo].[Referrals]'ORDER
Look at the last_user_seek column and see how frequently it is seeked. This is an important factor to decide whether the suggested index is needed or not
I created the following index based on the equality column and there was no include column NONCLUSTERED INDEX IDX_referrals_Account
CREATE
ON Referrals (Account,Hospitalcode,Deleted,uploaded )
GO
/* to see when was the last index was updated*/
DBCC SHOW_STATISTICS ('referrals', 'IDX_referrals_hospitalcode') GO
/* after adding the new index I updated the statistics of the table */
EXEC
GO sp_updatestats
GO
Finding the bad indexes
Indexes are considered bad if the total writes > total reads
--Find bad indexes for a single table (writes > reads)--find bad indexs SELECT
user_seeks OBJECT_NAME(s.object_id) AS 'Table Name', i.name AS 'Index Name', i.index_id, user_updates AS 'Total Writes', + user_scans + user_lookups AS 'Total Reads', user_updates - ( user_seeks + user_scans + user_lookups ) AS 'Difference' FROM sys.dm_db_index_usage_stats AS s WITH ( NOLOCK ) INNER JOIN sys.indexes AS i WITH ( NOLOCK ) ON s.object_id = i.object_id AND i.index_id = s.index_id WHERE OBJECTPROPERTY(s.object_id, 'IsUserTable') = 1 AND s.database_id = DB_ID() AND user_updates > ( user_seeks + user_scans + user_lookups ) AND i.index_id > 1 ORDER BY 'Difference' DESC, 'Total Writes' DESC, 'Total Reads'
--Find bad indexes for a single table (writes > reads)SELECT OBJECT_NAME(s.object_id) AS 'TableName',i.name AS 'IndexName',i.index_id,SUM(user_seeks) AS 'User Seeks',SUM(user_scans) AS 'User Scans',SUM(user_lookups) AS 'User Lookups',SUM(user_seeks + user_scans + user_lookups) AS 'Total Reads',SUM(user_updates) AS 'Total Writes'FROM
sys.dm_db_index_usage_stats AS sINNER JOIN sys.indexes AS i ON s.object_id = i.object_idAND i.index_id = s.index_idWHERE
OBJECTPROPERTY(s.object_id, 'IsUserTable') = 1AND s.database_id = DB_ID()AND OBJECT_NAME(s.object_id) = 'referrals'GROUP BY OBJECT_NAME(s.object_id),i.name,i.index_idORDER BY 'Total Writes' DESC,'Total Reads' DESC ; ASC ;
--Find bad indexes for a single table (writes > reads)--find bad indexs SELECT
user_seeks OBJECT_NAME(s.object_id) AS 'Table Name', i.name AS 'Index Name', i.index_id, user_updates AS 'Total Writes', + user_scans + user_lookups AS 'Total Reads', user_updates - ( user_seeks + user_scans + user_lookups ) AS 'Difference' FROM sys.dm_db_index_usage_stats AS s WITH ( NOLOCK ) INNER JOIN sys.indexes AS i WITH ( NOLOCK ) ON s.object_id = i.object_id AND i.index_id = s.index_id WHERE OBJECTPROPERTY(s.object_id, 'IsUserTable') = 1 AND s.database_id = DB_ID() AND user_updates > ( user_seeks + user_scans + user_lookups ) AND i.index_id > 1 ORDER BY 'Difference' DESC, 'Total Writes' DESC, 'Total Reads'
--Find bad indexes for a single table (writes > reads)SELECT OBJECT_NAME(s.object_id) AS 'TableName',i.name AS 'IndexName',i.index_id,SUM(user_seeks) AS 'User Seeks',SUM(user_scans) AS 'User Scans',SUM(user_lookups) AS 'User Lookups',SUM(user_seeks + user_scans + user_lookups) AS 'Total Reads',SUM(user_updates) AS 'Total Writes'FROM
sys.dm_db_index_usage_stats AS sINNER JOIN sys.indexes AS i ON s.object_id = i.object_idAND i.index_id = s.index_idWHERE
OBJECTPROPERTY(s.object_id, 'IsUserTable') = 1AND s.database_id = DB_ID()AND OBJECT_NAME(s.object_id) = 'referrals'GROUP BY OBJECT_NAME(s.object_id),i.name,i.index_idORDER BY 'Total Writes' DESC,'Total Reads' DESC ; ASC ;
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