SQL Server – Impact of Shrinking LDF File After Restoring Full Backup

ApexSQL has recently released a tool that can do this. It's ApexSQL Restore. I haven't tested it fully yet, but you have to connect to a SQL Server instance to do this. It attaches database backup file and creates MDF and LDF files for the database.

Here are the steps to reproduce this, tested on SQL 2012 SP1 Developer Edition. This does not occur on SQL 2008. To summarize, a database created in SQL 2012 while the model database is in SIMPLE recovery, that has a full backup taken while an extra log file exists, cannot create usable differential backups if that extra log file is ever deleted.

ALTER DATABASE [model] SET RECOVERY SIMPLE
GO
CREATE DATABASE [DefunctTest]
GO
ALTER DATABASE [DefunctTest] ADD LOG FILE ( NAME = N'DefunctTest_log2', FILENAME = N'D:\DefunctTest_log2.ldf' , SIZE = 25600KB , FILEGROWTH = 10%)
GO
BACKUP DATABASE [DefunctTest] TO DISK = 'D:\DefunctTestPostLogFile.bak' WITH INIT
GO
ALTER DATABASE [DefunctTest]  REMOVE FILE [DefunctTest_log2]
GO

BACKUP DATABASE [DefunctTest] TO DISK = 'D:\DefunctTestFull.bak' WITH INIT
GO
BACKUP DATABASE [DefunctTest] TO DISK = 'D:\DefunctTestDiff.bak' WITH DIFFERENTIAL, INIT
GO
--Show that the backups only have the one log file.
RESTORE FILELISTONLY FROM DISK = 'D:\DefunctTestFull.bak'
RESTORE FILELISTONLY FROM DISK = 'D:\DefunctTestDiff.bak'
GO
RESTORE DATABASE [DefunctTest2] FROM DISK = 'D:\DefunctTestFull.bak' WITH 
MOVE 'DefunctTest' TO 'D:\DefunctTest2.mdf',
MOVE 'DefunctTest_log' TO 'D:\DefunctTest2_log.ldf', REPLACE, NORECOVERY
GO
--This restore will have the error.
RESTORE DATABASE [DefunctTest2] FROM DISK = 'D:\DefunctTestDiff.bak' WITH RECOVERY
GO

USE [DefunctTest2]
SELECT * FROM sys.database_files
GO

I submitted a Connect item for this bug here. The only way I've been able to remove this defunct file is to detach the database, and re-attach with ATTACH_REBUILD_LOG.

UPDATE: The bug that creates this scenario in my repro script seems to have been fixed by this KB: https://support.microsoft.com/en-us/kb/2830400. From the comments it appears an additional fix is available for SQL2012/2014, the scenarios seem very similar: https://support.microsoft.com/en-us/kb/3009576