the data file, log file or both.
Thursday, 4 November 2021
Full Backup Vs. Differential Backup Vs. Log Backup
the data file, log file or both.
Monday, 1 November 2021
Removing Invalid Logins (Both Server and Database Principals) from SQL Server
CREATE TABLE #InvalidUsers( [SID] VARBINARY(85) ,LOGIN_NAME SYSNAME ) INSERT INTO #InvalidUsers ( [SID] ,LOGIN_NAME ) EXEC sys.sp_validatelogins
- Whether the user owns a schema in the database (if so we need to change the schema ownership to dbo)
- Whether the user owns a the database. If so we need to change db ownership to a different user. In this example I will be changing the ownership to "sa"
We will insert the details into another temporary table. I will explain part by part, but once the script is completed you can execute it as a whole. I have provided the completed script at the end.
We will use another system stored procedure to execute a query in all the databases in the SQL Server instance (sys.sp_MSforeachdb)
DECLARE @LoginName AS sysname ,@Sql AS NVARCHAR(2000) DECLARE cur CURSOR LOCAL READ_ONLY FORWARD_ONLY FOR SELECT LOGIN_NAME FROM #InvalidUsers OPEN cur FETCH NEXT FROM cur INTO @LoginName WHILE @@FETCH_STATUS = 0 BEGIN SET @Sql = CONCAT( 'USE ?;INSERT INTO #InvalidUserDbInfo SELECT DB_NAME(),DP.sid,DP.name, S.[name] as OwnedSchema FROM sys.database_principals AS DP LEFT JOIN sys.schemas as S on S.principal_id = DP.principal_id WHERE [type] = ''U'' and DP.name = ''',@LoginName,'''' ) EXEC sys.sp_MSforeachdb @Sql FETCH NEXT FROM cur INTO @LoginName END CLOSE cur DEALLOCATE cur
DECLARE @LoginName AS sysname ,@Sql AS NVARCHAR(2000) ,@DBName AS NVARCHAR(128) ,@DbNameCurrent AS NVARCHAR(128) = '' ,@SqlSyntax AS NVARCHAR(MAX) = '' ,@OwnedSchema AS VARCHAR(128) DECLARE cur CURSOR LOCAL READ_ONLY FORWARD_ONLY FOR SELECT IUDI.DBNAME ,IUDI.LOGIN_NAME ,IUDI.OWNED_SCH FROM #InvalidUserDbInfo AS IUDI WHERE IUDI.DBNAME <> 'master' ORDER BY IUDI.DBNAME OPEN cur FETCH NEXT FROM cur INTO @DBName,@LoginName,@OwnedSchema WHILE @@FETCH_STATUS = 0 BEGIN IF @DbNameCurrent <> @DBName BEGIN IF @DbNameCurrent <> '' SET @SqlSyntax += CONCAT(CHAR(13),'---------------------------------',CHAR(13),CHAR(13)) SET @SqlSyntax += CONCAT('USE [',@DBName,'];',CHAR(13),CHAR(13)) SET @DbNameCurrent = @DBName END IF (ISNULL(@OwnedSchema,'') <> '' AND ISNULL(@OwnedSchema,'') <> @LoginName) BEGIN SET @SqlSyntax += CONCAT('ALTER AUTHORIZATION ON SCHEMA::[',@OwnedSchema,'] TO [dbo]', CHAR(13)) END SET @SqlSyntax += CONCAT('DROP USER IF EXISTS [',@LoginName,']',CHAR(13)) FETCH NEXT FROM cur INTO @DBName,@LoginName,@OwnedSchema END CLOSE cur DEALLOCATE cur SELECT CAST('<![CDATA[' + CHAR(13) + @SqlSyntax + CHAR(13) + ']]> ' AS XML) AS CleanupScript_Step_2
DECLARE @SqlSyntax AS NVARCHAR(MAX) = '' SET @SqlSyntax += CONCAT(' --== Changing Database Ownership ==--',CHAR(13),CHAR(13),'USE master;',CHAR(13)) SELECT @SqlSyntax = @SqlSyntax + CHAR(13) + CONCAT('ALTER AUTHORIZATION ON DATABASE::[',S.[name],'] TO [sa]') FROM sys.databases AS S JOIN #InvalidUsers AS U ON SUSER_SNAME(S.owner_sid) = U.LOGIN_NAME SET @SqlSyntax+= CONCAT(CHAR(13),CHAR(13)) ------------------------------------------------------------------------------------------ SELECT @SqlSyntax = @SqlSyntax + CHAR(13) + CONCAT('IF EXISTS (SELECT 0 FROM [sys].[server_principals] AS [SP] WHERE [SP].[name] = N''' ,U.LOGIN_NAME ,''')' ,CHAR(13),CHAR(9) ,'DROP LOGIN [',U.LOGIN_NAME,']',CHAR(13),CHAR(13) ) FROM [sys].[server_principals] AS [SP] JOIN #InvalidUsers AS U ON U.LOGIN_NAME = SP.[name] SELECT CAST('<![CDATA[' + CHAR(13) + @SqlSyntax + CHAR(13) + ']]> ' AS XML) AS CleanupScript_Step_3
CREATE TABLE #InvalidUsers( [SID] VARBINARY(85) ,LOGIN_NAME SYSNAME ) INSERT INTO #InvalidUsers ( [SID] ,LOGIN_NAME ) EXEC sys.sp_validatelogins ------------------------------------------------------------------------------------------ CREATE TABLE #InvalidUserDbInfo( DBNAME NVARCHAR(128) ,[SID] VARBINARY(85) ,LOGIN_NAME SYSNAME ,OWNED_SCH VARCHAR(128) ) DECLARE @LoginName AS sysname ,@Sql AS NVARCHAR(2000) ,@DBName AS NVARCHAR(128) ,@DbNameCurrent AS NVARCHAR(128) = '' ,@SqlSyntax AS NVARCHAR(MAX) = '' ,@OwnedSchema AS VARCHAR(128) DECLARE cur CURSOR LOCAL READ_ONLY FORWARD_ONLY FOR SELECT LOGIN_NAME FROM #InvalidUsers OPEN cur FETCH NEXT FROM cur INTO @LoginName WHILE @@FETCH_STATUS = 0 BEGIN SET @Sql = CONCAT( 'USE ?;INSERT INTO #InvalidUserDbInfo SELECT DB_NAME(),DP.sid,DP.name, S.[name] as OwnedSchema FROM sys.database_principals AS DP LEFT JOIN sys.schemas as S on S.principal_id = DP.principal_id WHERE [type] = ''U'' and DP.name = ''',@LoginName,'''' ) EXEC sys.sp_MSforeachdb @Sql FETCH NEXT FROM cur INTO @LoginName END CLOSE cur DEALLOCATE cur ------------------------------------------------------------------------------------------ DECLARE cur CURSOR LOCAL READ_ONLY FORWARD_ONLY FOR SELECT IUDI.DBNAME ,IUDI.LOGIN_NAME ,IUDI.OWNED_SCH FROM #InvalidUserDbInfo AS IUDI WHERE IUDI.DBNAME <> 'master' ORDER BY IUDI.DBNAME OPEN cur FETCH NEXT FROM cur INTO @DBName,@LoginName,@OwnedSchema WHILE @@FETCH_STATUS = 0 BEGIN IF @DbNameCurrent <> @DBName BEGIN IF @DbNameCurrent <> '' SET @SqlSyntax += CONCAT(CHAR(13),'---------------------------------',CHAR(13),CHAR(13)) SET @SqlSyntax += CONCAT('USE [',@DBName,'];',CHAR(13),CHAR(13)) SET @DbNameCurrent = @DBName END IF (ISNULL(@OwnedSchema,'') <> '' AND ISNULL(@OwnedSchema,'') <> @LoginName) BEGIN SET @SqlSyntax += CONCAT('ALTER AUTHORIZATION ON SCHEMA::[',@OwnedSchema,'] TO [dbo]', CHAR(13)) END SET @SqlSyntax += CONCAT('DROP USER IF EXISTS [',@LoginName,']',CHAR(13)) FETCH NEXT FROM cur INTO @DBName,@LoginName,@OwnedSchema END CLOSE cur DEALLOCATE cur ------------------------------------------------------------------------------------------ SET @SqlSyntax += CONCAT(CHAR(13),CHAR(13) ,' --== Changing Database Ownership ==--',CHAR(13),CHAR(13) ,'USE master;',CHAR(13)) SELECT @SqlSyntax = @SqlSyntax + CHAR(13) + CONCAT('ALTER AUTHORIZATION ON DATABASE::[',S.[name],'] TO [sa]') FROM sys.databases AS S JOIN #InvalidUsers AS U ON SUSER_SNAME(S.owner_sid) = U.LOGIN_NAME SET @SqlSyntax+= CONCAT(CHAR(13),CHAR(13)) ------------------------------------------------------------------------------------------ SELECT @SqlSyntax = @SqlSyntax + CHAR(13) + CONCAT('IF EXISTS (SELECT 0 FROM [sys].[server_principals] AS [SP] WHERE [SP].[name] = N''' ,U.LOGIN_NAME,''')' ,CHAR(13),CHAR(9) ,'DROP LOGIN [',U.LOGIN_NAME,']',CHAR(13),CHAR(13)) FROM [sys].[server_principals] AS [SP] JOIN #InvalidUsers AS U ON U.LOGIN_NAME = SP.[name] SELECT CAST('<![CDATA[' + CHAR(13) + @SqlSyntax + CHAR(13) + ']]> ' AS XML) AS CleanupScript_Step_3
Sunday, 31 October 2021
Attaching SQL Database with FILESTREAM data
Have you ever come across a situation where you need to attach a database using existing files (mdf, ldf & file stream data), but you don't have an option to mention the file stream folder when you use SSMS.
This won't be an issue if the filestream folder resides on its original path.
Let's look at an example. I have SQL data, log and filestream data which I will first attach using SSMS.
- Right-click on the database folder in SSMS and choose "Attach"
- Click the "Add" button and choose the data file (.mdf). Upon selecting the mdf file it will list the associated ldf file as well. But make sure to change the path accordingly from the second pane.
- Click on Ok.
Even if you try to generate the scripts using SSMS it doesn't provide you with the option to include the filestream folder.
USE [master] GO CREATE DATABASE [SampleSqlDatabase] ON ( FILENAME = N'D:\_SQL_DATA\SampleSqlDatabase_Data.mdf' ), ( FILENAME = N'D:\_SQL_LOG\SampleSqlDatabase_Log.ldf' ) FOR ATTACH GO
We can use the above code snippet and include the file stream path.
USE [master] GO CREATE DATABASE [SampleSqlDatabase] ON (FILENAME = N'D:\_SQL_DATA\SampleSqlDatabase_Data.mdf'), (FILENAME = N'D:\_SQL_LOG\SampleSqlDatabase_Log.ldf'), FILEGROUP NewFSGroup CONTAINS FILESTREAM ( NAME = 'NewDatabaseFileStream' ,FILENAME = 'D:\_SQL_DATA\SampleSqlDatabase_FSData_New' ) FOR ATTACH GO
Then you will be able to attach the database without an issue. You can use any name for the FILEGROUP and NAME (under the FILEGROUP). It doesn't need to be the same as your source database.
Hope this will be a helpful tip to you.
SQL Server Transaction Log file behaviour in Full Recovery Mode
In a previous blog post, I have explained different types of recovery models in SQL Server databases. During the explanations, I have stated that the transaction log data will be truncated during certain backup types. We will look into this more closely and see how it works.
Note: Even the details are removed from the transaction log file, the physical size may not change unless you issue a DBCC SHRINKFILE command. Only the file space will be re-used once the details are truncated.
We will start with creating a sample database named 'SqlTransactionLogExample'
USE master; GO CREATE DATABASE [SqlTransactionLogExample]; --== Makesure the database is in "Full" recovery model ==-- SELECT [name] ,DATABASEPROPERTYEX([name],'Recovery') AS recovery_model FROM sys.databases WHERE [name] = 'SqlTransactionLogExample'
We will create one table and insert records (1,000,000 rows to see a significant change in the file size).
USE SqlTransactionLogExample;
GO
CREATE TABLE dbo.UidInformation(
Id UNIQUEIDENTIFIER NOT NULL
,PayLoad CHAR(1000) NOT NULL CONSTRAINT [DF_SampleTable] DEFAULT (SPACE(1000))
)
INSERT INTO dbo.UidInformation (
Id
,PayLoad
)
SELECT
NEWID() AS Id,
([100000].Num
+ [10000].Num
+ [1000].Num
+ [100].Num
+ [10].Num
+ [1].Num) AS PayLoad
FROM (
SELECT 1 AS Num UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL
SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6
UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9 UNION ALL
SELECT 0
) AS [1]
CROSS JOIN (
SELECT 10 AS Num UNION ALL SELECT 20 UNION ALL SELECT 30 UNION ALL
SELECT 40 UNION ALL SELECT 50 UNION ALL SELECT 60 UNION ALL
SELECT 70 UNION ALL SELECT 80 UNION ALL SELECT 90 UNION ALL
SELECT 0
) AS [10]
CROSS JOIN (
SELECT 100 AS Num UNION ALL SELECT 200 UNION ALL SELECT 300
UNION ALL SELECT 400 UNION ALL SELECT 500 UNION ALL SELECT 600
UNION ALL SELECT 700 UNION ALL SELECT 800 UNION ALL SELECT 900
UNION ALL SELECT 0
) AS [100]
CROSS JOIN (
SELECT 1000 AS Num UNION ALL SELECT 2000 UNION ALL SELECT 3000
UNION ALL SELECT 4000 UNION ALL SELECT 5000 UNION ALL SELECT 6000
UNION ALL SELECT 7000 UNION ALL SELECT 8000 UNION ALL SELECT 9000
UNION ALL SELECT 0
) AS [1000]
CROSS JOIN (
SELECT 10000 AS Num UNION ALL SELECT 20000 UNION ALL SELECT 30000
UNION ALL SELECT 40000 UNION ALL SELECT 50000 UNION ALL SELECT 60000
UNION ALL SELECT 70000 UNION ALL SELECT 80000 UNION ALL SELECT 90000
UNION ALL SELECT 0
) AS [10000]
CROSS JOIN (
SELECT 100000 AS Num UNION ALL SELECT 200000 UNION ALL SELECT 300000
UNION ALL SELECT 400000 UNION ALL SELECT 500000 UNION ALL SELECT 600000
UNION ALL SELECT 700000 UNION ALL SELECT 800000 UNION ALL SELECT 900000
UNION ALL SELECT 0
) AS [100000]
WHERE(
[100000].Num
+ [10000].Num
+ [1000].Num
+ [100].Num
+ [10].Num
+ [1].Num
) BETWEEN 1 AND 1000000
ORDER BY ([100000].Num + [10000].Num + [1000].Num + [100].Num + [10].Num + [1].Num)
Now we will inspect the number of entries in the transaction log.
SELECT COUNT(*) FROM sys.fn_dblog (NULL,NULL) --Returns 2511475
Note: Record count may be varied in the transaction log of your database.
We will check the size of the transaction log file
Now we will take a full database backup
USE master; GO BACKUP DATABASE [SqlTransactionLogExample] TO DISK = 'D:\_SQL_BACKUP\SqlTransactionLogExample_FullDB_Backup.bak' Now we will inspect number of entries in the transaction log file again. USE SqlTransactionLogExample GO SELECT COUNT(*) FROM sys.fn_dblog (NULL,NULL) --Returns 2511475
Note: There is a slight increment of the record count since there are new entries written to the log file during the database backup.
We will now inspect the transaction log entries
SELECT COUNT(*) FROM sys.fn_dblog (NULL,NULL) -- Returns 2511545
We will now take a backup of the transaction log
BACKUP LOG [SqlTransactionLogExample] TO DISK = 'D:\_SQL_BACKUP\SqlTransactionLogExample_LogBackup_AfterInsert.bak'
And if we inspect the number of entries in the log file it has drastically reduced.
SELECT COUNT(*) FROM sys.fn_dblog (NULL,NULL) --Returns 10
However, the space consumed by the log file is still the same. This is the reason I have mentioned it previously. In order to release the space, we have to issue the DBCC SHRINKFILE command.
--This is to find the name of the logical log file name SELECT * FROM sys.sysfiles --SqlTransactionLogExample_log DBCC SHRINKFILE('SqlTransactionLogExample_log',1)
Hope this will be helpful to you.