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Posts Categorized / Database Migrations

  • Mar 09 / 2017
  • 0
Database Migrations, dbDigger, T-SQL Scripts

Code snippets for database migration task

Following are some code snippets that i used during a database migration task from one server to another. Backup restore method is used in this migration task

DB list on source server

Get the database list on source server that are required to migrate

select name, user_access, state_desc, create_date
from sys.databases
where name in
( 'comma separated list of specific databases to be migrated')
order by name

Note DB properties

Note the important database properties on source server so that we may verify these on destination server after migration is complete.

select name, is_published, is_subscribed, is_cdc_enabled, is_trustworthy_on, is_read_only

from sys.databases where name in
( 'comma separated list of specific databases to be migrated')
order by name

Size of DBs

Get size of all databases that are to be migrated. It would help to estimate the disk capacity on destination and also the time estimate for backup and restore process.

SELECT DB_NAME(database_id) AS DatabaseName, type_desc,
cast(sum( size* 8.0 / 1024)/1024 as DECIMAL(18,3)) [Size(GB)]
FROM sys.master_files
where DB_NAME(database_id) in
( 'comma separated list of specific databases to be migrated')
GROUP BY DB_NAME(database_id), type_desc
ORDER BY DB_NAME(database_id), type_desc DESC

Get which DBs are in Avaiability Group

SELECT
AG.name AS [AvailabilityGroupName],
ISNULL(agstates.primary_replica, '') AS [PrimaryReplicaServerName],
dbcs.database_name AS [DatabaseName]
FROM master.sys.availability_groups AS AG
LEFT OUTER JOIN master.sys.dm_hadr_availability_group_states as agstates
ON AG.group_id = agstates.group_id
INNER JOIN master.sys.availability_replicas AS AR
ON AG.group_id = AR.group_id
INNER JOIN master.sys.dm_hadr_availability_replica_states AS arstates
ON AR.replica_id = arstates.replica_id AND arstates.is_local = 1
INNER JOIN master.sys.dm_hadr_database_replica_cluster_states AS dbcs
ON arstates.replica_id = dbcs.replica_id
where dbcs.database_name in ('Comma seperated list of DBs to be migrated')

Set DBs to READ ONLY and Restricted mode on source server

Before backing up the databases we will do following operations for each DB. As here i have databases in AG so i also included command to set DB out of AG so that i may put it to READ ONLY mode next.

ALTER AVAILABILITY GROUP [AvailabilityNodeName] REMOVE DATABASE [DBName]
GO
ALTER DATABASE [DBName] SET  READ_ONLY WITH ROLLBACK IMMEDIATE
GO
ALTER DATABASE [DBName] SET  RESTRICTED_USER WITH ROLLBACK IMMEDIATE
GO

Backup Databases

We will take backup of all databases through following script. Go through the option used for backup and also put a valid path. Backup file name will be generated automatically.

-- Declare cursor for database names
DECLARE BackupCursor CURSOR FOR
SELECT name FROM sys.databases
WHERE name in
( 'Comma seperated list of databases')

-- Declare variable to hold DBName
declare @Db_name varchar(100)

OPEN BackupCursor
FETCH NEXT FROM BackupCursor INTO @Db_name

WHILE (@@FETCH_STATUS <> -1)
BEGIN

-- Backup code
declare @Backup_Path Varchar(500) = 'Full Backup Path here'

DECLARE @fileName VARCHAR(400)  = @Backup_Path +'\'+ replace(@@servername, '\','_' ) + '_' + @Db_name+ '_' + 'FULL'+ '_' + LEFT(CONVERT(VARCHAR,getdate(), 120), 10)
+'.BAK'   -- filename for backup

DECLARE @sqlCommand varchar(1000)
SET @sqlCommand = 'BACKUP DATABASE ['+ @Db_name+'] TO DISK ='+   ''''+@fileName+ ''' WITH COPY_ONLY, CHECKSUM, INIT,COMPRESSION, STATS = 10;'

EXEC (@sqlCommand)

RESTORE  verifyonly from disk = @fileName
print 'Backup file path is '+@fileName

FETCH NEXT FROM BackupCursor INTO @Db_name
END
-- Close and deallocate the cursor
CLOSE BackupCursor
DEALLOCATE BackupCursor

 

Get restore command for each DB one by one

Put DB name in first line of script one by one and get the restore commands for last full backup of that specific database

     declare @db_name varchar(100) = 'DBName'

Declare @tmp table
(StartDT datetime, BKP_Type char(1), RestorePart Varchar(2000), FilePart varchar(max))

If exists (select name from sys.databases where name = @Db_name)

begin
Insert @tmp
SELECT s.[backup_start_date] ,s.[type]
,'Restore database ' + s.[database_name] +'
From Disk = ''' + Replace (replace (B.[physical_device_name], 'SQL Backups 2', 'SQL Backups 2'), 'DROPOFF', 'RECOVERY') + '''
with replace, keep_cdc, recovery, stats =1 ' as RestorePart    ,
'      , Move ''' + f.[logical_name] + ''''
+ ' TO ''' + f.[physical_name] + '''' as FilePart
FROM [msdb].[dbo].[backupset] S
inner join [msdb].[dbo].[backupfile] F
on S.backup_set_id = f.backup_set_id
inner join [msdb].[dbo].[backupmediafamily] B
on s.media_set_id = b.media_set_id
where s.type ='d'
and s.database_name = @Db_name
and s.backup_start_date =
(select max(s.backup_start_date)
from [msdb].[dbo].[backupset] s
where s.type ='d' and s.database_name = @Db_name )
order by s.backup_set_id desc

--select * from @tmp

select distinct '-- Latest Full backup for database ' + @Db_name + ' is from ' + cast(StartDT as varchar(20))
from @tmp

Select '--Run this on DR replica for initial restore:' as [--RestoreStatement]
union all
Select Distinct RestorePart
from @tmp
union all
select FilePart from @tmp

End
ELSE
Select 'Database ' + @Db_name + ' does not exist on ' + @@Servername
Set nocount off

Set databases to READ WRITE mode on destination server

ALTER DATABASE [AD_MgmtMaster] SET  MULTI_USER WITH ROLLBACK IMMEDIATE
GO
ALTER DATABASE [AD_MgmtMaster] SET  READ_WRITE WITH ROLLBACK IMMEDIATE
GO

 

Fix and verify the orphan users

</pre>
-- Fix orphaned users in DB
<pre>EXEC     [dbo].[spFixOrphanUsers]    @DatabaseNM = 'DBNameHere'
GO

-- Verify the orphaned users in DB
USE DBNameHere
GO
sp_change_users_login @Action='Report'
GO

 

Update the DB properties

Following scripts will generate commands to fix the specific database property.

-- Set DB owner to sa
select suser_sname(owner_sid) , 'ALTER AUTHORIZATION ON DATABASE::'+name+'  TO sa;'
from sys.databases
where suser_sname(owner_sid) &lt;&gt; 'sa'

-- Set compatibility level
select 'ALTER DATABASE ['+name+'] SET COMPATIBILITY_LEVEL = 120;'
from sys.databases
where COMPATIBILITY_LEVEL &lt;&gt; 120

-- Set AutoCreateStats
select 'ALTER DATABASE ['+name+'] SET AUTO_CREATE_STATISTICS ON;'
from sys.databases
where is_auto_create_stats_on = 0

-- Set AutoUpdateStats
select 'ALTER DATABASE ['+name+'] SET AUTO_UPDATE_STATISTICS ON;'
from sys.databases
where is_auto_update_stats_on = 0

 

 

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