skreebydba

It's been awhile since I've posted here, and I've already fallen behind on my New Year's resolution to post once a week. I will do what I can to keep up over the next 51 weeks.

For the past few months, I've been working to standardize the backup processes at my current job. Recently, I've needed to develop a process to restore a read-only copy of a production database using the most recent full backup file and any subsequent log backup files. The procedure below does that. It will work for database backups containing multiple backup files and databases containing multiple data files. However, if you have more than one log file in your database, you are out of luck. See Paul Randal's post Multiple Log Files and Why They're Bad for an excellent explanation of why you shouldn't do that. I will add error handling to deal with this scenario this weekend.

I hope you can put this to use. Let me know if you have questions.

USE YourDatabaseName
GO
-- =============================================
-- Frank Gill - skreebydba.com
-- sp_AutomateDatabaseRestores
-- This script is provided with no guarantees
-- Please run in you test environment before deploying to production
-- The author takes no responsibility if your server descends into a smoking hole
-- =============================================

-- Drop stored procedure if it already exists
IF EXISTS (
  SELECT * 
    FROM INFORMATION_SCHEMA.ROUTINES 
   WHERE SPECIFIC_SCHEMA = N'dbo'
     AND SPECIFIC_NAME = N'sp_AutomateDatabaseRestores' 
)
   DROP PROCEDURE dbo.sp_AutomateDatabaseRestores
GO

CREATE PROCEDURE dbo.sp_AutomateDatabaseRestores
	@sourcedbname SYSNAME, 
	@restoredbname SYSNAME,
	@droprestoredb TINYINT = 1,
	@noexec TINYINT = 0
AS
	
SET NOCOUNT ON

--Drop temp tables if they exist
IF OBJECT_ID('tempdb..#backupfiles') IS NOT NULL
BEGIN

	DROP TABLE #backupfiles
	
END 

IF OBJECT_ID('tempdb..#databasefiles') IS NOT NULL
BEGIN

	DROP TABLE #databasefiles
	
END

--Create temp tables
CREATE TABLE #backupfiles
(physicalfilename VARCHAR(2000)
,recoverymodel CHAR(4))

CREATE TABLE #databasefiles
(DatabaseName SYSNAME
,LogicalName SYSNAME
,PhysicalName VARCHAR(2000)
,filetype TINYINT)

--Declare local variables
DECLARE @filecount SMALLINT
DECLARE @fullfilecount SMALLINT
DECLARE @loopcount SMALLINT
DECLARE @datafileloopcount SMALLINT
DECLARE @backuploopcount SMALLINT
DECLARE @backupfile VARCHAR(2000)
DECLARE @sqlstr VARCHAR(MAX)
DECLARE @backupfiletype CHAR(4)
DECLARE @datafilecount SMALLINT
DECLARE @logfilecount SMALLINT
DECLARE @logbackupcount SMALLINT
DECLARE @datafile VARCHAR(2000)
DECLARE @moveparm VARCHAR(2000)
DECLARE @fromstatement VARCHAR(2000)
DECLARE @logfile SYSNAME
DECLARE @physlogfile VARCHAR(2000)
DECLARE @physdatafile VARCHAR(2000)

--Drop the restored database if it exists and @droprestoredb = 1
IF EXISTS(SELECT 1 FROM sys.databases WHERE name = @restoredbname) AND @droprestoredb = 1
BEGIN

	SET @sqlstr = 'DROP DATABASE ' + @restoredbname
	EXEC (@sqlstr)
	
END

--Initialize variables
SET @moveparm = ' WITH'
SET @fromstatement = ' FROM '
SET @loopcount = 1
SET @datafileloopcount = 1
SET @backuploopcount = 1


--Build dynamic SQL to get a list of data and log files for the source database
SET @sqlstr = 'INSERT INTO #databasefiles SELECT ' + '''' + @sourcedbname + '''' + ' AS DatabaseName, name, physical_name, type 
FROM ' + @sourcedbname + '.sys.database_files'

--Execute dynamic SQL to return data and log files for the source database
EXEC (@sqlstr)

--Get counts of data files and log files
SELECT @datafilecount = COUNT(*) FROM #databasefiles WHERE filetype = 0
SELECT @logfilecount  = COUNT(*) FROM #databasefiles WHERE filetype = 1

--Get the logical and physical log file names
SELECT @logfile = LogicalName, @physlogfile = REPLACE(PhysicalName,@sourcedbname,@restoredbname)
FROM #databasefiles
WHERE filetype = 1

--If the database contains one data file, build the MOVE clause for a single file
IF @datafilecount = 1
BEGIN

	SELECT @datafile = LogicalName, @physdatafile = REPLACE(PhysicalName,@sourcedbname,@restoredbname) 
	FROM #databasefiles
	WHERE filetype = 0
	
	SET @moveparm = @moveparm + ' MOVE ' + '''' + @datafile + '''' + ' TO ' + '''' + @physdatafile + '''' + ',' + ' MOVE ' + '''' + @logfile + '''' + ' TO ' + '''' + @physlogfile + '''' + ', NORECOVERY' 
END
ELSE
--If the database contains more than one data file, loop through the list of files and build a multi-file MOVE statement
IF @datafilecount > 1
BEGIN
	
	--SELECT @datafileloopcount, @datafilecount
	WHILE @datafileloopcount <= @datafilecount
	BEGIN
		
		--SELECT TOP (1) LogicalName, REPLACE(PhysicalName,@sourcedbname,@restoredbname) FROM #databasefiles WHERE filetype = 0
		SET @physdatafile = (SELECT TOP (1) REPLACE(PhysicalName,@sourcedbname,@restoredbname) FROM #databasefiles WHERE filetype = 0)
		SET @datafile = (SELECT TOP (1) LogicalName FROM #databasefiles WHERE filetype = 0)		
		SET @moveparm = @moveparm + ' MOVE ' + '''' + @datafile + '''' + ' TO ' + '''' + @physdatafile + '''' + ','
		DELETE TOP (1) FROM #databasefiles WHERE filetype = 0
		SET @datafileloopcount += 1
		
	END	
	
	--Append the MOVE command for the log file to the MOVE clause and set it to NORECOVERY
	SET @moveparm = @moveparm + ' MOVE ' + '''' + @logfile + '''' + ' TO ' + '''' + @physlogfile + '''' + ', NORECOVERY'
		
END

IF @droprestoredb = 0
BEGIN

	SET @moveparm = @moveparm + ', REPLACE'
	
END

--Get the most recent full backup file for the source database and insert it into the #backupfiles temp table
INSERT INTO #backupfiles
SELECT
b.physical_device_name, 'FULL' AS [RecoveryModel]
from msdb.dbo.backupset a join msdb.dbo.backupmediafamily b
  on a.media_set_id = b.media_set_id
where a.database_name = @sourcedbname
AND backup_finish_date =
	(SELECT MAX(c.backup_finish_date)
		FROM msdb.dbo.backupset c 
		INNER JOIN msdb.dbo.backupmediafamily d
		ON c.media_set_id = d.media_set_id 
		WHERE c.database_name = @sourcedbname
		AND REVERSE(SUBSTRING(REVERSE(d.physical_device_name),1,3)) = 'BAK')
order by a.backup_finish_date ASC

--Get all log backupfiles run after the latest full backup and insert it into the #backupfiles temp table
INSERT INTO #backupfiles
SELECT
b.physical_device_name, 'LOG'  AS [RecoveryModel]
from msdb.dbo.backupset a join msdb.dbo.backupmediafamily b
  on a.media_set_id = b.media_set_id
where a.database_name = @sourcedbname
AND REVERSE(SUBSTRING(REVERSE(b.physical_device_name),1,3)) = 'TRN'
AND backup_finish_date >
	(SELECT MAX(c.backup_start_date)
		FROM msdb.dbo.backupset c 
		INNER JOIN msdb.dbo.backupmediafamily d
		ON c.media_set_id = d.media_set_id 
		WHERE c.database_name = @sourcedbname
		AND REVERSE(SUBSTRING(REVERSE(d.physical_device_name),1,3)) = 'BAK')
order by a.backup_finish_date ASC

--Get counts of all backup files, full backup files, and log backup files for use in loop processing below
SELECT @filecount = COUNT(*) FROM #backupfiles
SELECT @fullfilecount = COUNT(*) FROM #backupfiles WHERE recoverymodel = 'FULL'
SELECT @logbackupcount = COUNT(*) FROM #backupfiles WHERE recoverymodel = 'LOG'

--While backup files exists, loop through them to generate the restore statement
WHILE @loopcount <= @filecount
BEGIN

	--Get the top backup file from the temp table	
	SET @backupfiletype = (SELECT TOP 1 recoverymodel FROM #backupfiles)
	
	--If it is a full backup file, build the restore statement
	IF @backupfiletype = 'FULL'
	BEGIN
		
		--If there are no log backups to apply, replace NORECOVERY with RECOVERY in the MOVE clause
		IF @logbackupcount = 0
		BEGIN
		
			SET @moveparm = REPLACE(@moveparm, 'NORECOVERY', 'RECOVERY')
			
		END
	
		--If there is a single full backup file, build the RESTORE statement with that file
		IF @fullfilecount = 1
		BEGIN
		
			SET @backupfile = (SELECT TOP 1 physicalfilename FROM #backupfiles)
		
			SET @sqlstr = 'RESTORE DATABASE ' + @restoredbname + ' FROM DISK = ' + '''' + @backupfile + '''' + @moveparm
			--PRINT @sqlstr
			DELETE TOP (1) FROM #backupfiles
			
		END
		--If there is more than one full backup file, build the RESTORE command for all full backup files
		ELSE IF @fullfilecount > 1
		BEGIN
			
			WHILE @backuploopcount <= @fullfilecount
			BEGIN
			
				SET @backupfile = (SELECT TOP 1 physicalfilename FROM #backupfiles WHERE recoverymodel = 'FULL')
				SET @fromstatement = @fromstatement + 'DISK = ' + '''' + @backupfile + '''' + ','
				DELETE TOP (1) FROM #backupfiles WHERE recoverymodel = 'FULL'
				SET @backuploopcount += 1
			
			END
			
			--Truncate the trailing comma from the FROM clause
			SET @fromstatement = SUBSTRING(@fromstatement,1,(LEN(@fromstatement) - 1))
			SET @sqlstr = 'RESTORE DATABASE ' + @restoredbname + @fromstatement + @moveparm
			SET @loopcount += 1
			--PRINT @sqlstr
			
		END
			
			
	END
	--If it is a log backup file, build a RESTORE log statement
	--One RESTORE datement will be built for each log backup file
	ELSE IF @backupfiletype = 'LOG'
	BEGIN
	
		SET @backupfile = (SELECT TOP 1 physicalfilename FROM #backupfiles)

		SET @sqlstr = 'RESTORE LOG ' + @restoredbname + ' FROM DISK = ' + '''' + @backupfile + ''''
		
		--If there is another log backup file, set the RESTORE to WITH NORECOVERY
		IF (SELECT COUNT(*) FROM #backupfiles) > 1
		BEGIN
		
			SET @sqlstr = @sqlstr + ' WITH NORECOVERY'
			
		END
		--If there is not another log backup file, set the RESTORE to WITH RECOVERY
		ELSE
		BEGIN
		
			SET @sqlstr = @sqlstr + ' WITH RECOVERY'
		
		END
		
		DELETE TOP (1) FROM #backupfiles

	
	END
	
	--If @noexec = 1, PRINT @sqlstr
	IF @noexec = 1
	BEGIN
	
		PRINT @sqlstr
	
	END
	--If @noexec <> 1, EXEC @sqlstr
	ELSE 
	BEGIN
	
		EXEC (@sqlstr)
		
	END
	
	--Increment the loop count and continue processing backup files
	SET @loopcount += 1
	
END


GO