The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 7: FILESTREAM Database AdministrationUPDATE TOP (1) Items SETItemImage = CAST(REPLICATE('A', 2048) AS VARBINARY(MAX))Listing 7-17:Updating a FILESTREAM data value to create a garbage file.After the update, you will see that there are two files in the FILESTREAM data container.A new file has been generated with the modified value, and the previous file (whose nameyou noted) is now garbage.My tests show that deleting this garbage file manually, without waiting for the garbagecollector, does not corrupt the database in present versions of SQL Server. After deletingthe garbage files, I ran DBCC CHECKDB and no error was reported. This was surprising tome, because the garbage files are tracked internally through the FILESTREAM tombstonetable and I would expect SQL Server to report an error if one goes missing.As has been stressed several times already, it is not a good idea to touch the FILESTREAMdata container directly. All access to the FILESTREAM data should be done through SQLServer – either using T-SQL or through the Win32 API calls. Do not ever attempt to cleanFILESTREAM garbage by yourself, unless there is an emergency where you are runningout of storage space and you badly need some of those garbage files to be removed (and,of course, you fully understand the risks of touching FILESTREAM data directly).Querying FILESTREAM DatabasesSQL Server has a number of FILESTREAM-related system views that you can use to queryadditional information about the FILESTREAM storage and activities. They are listed inChapter 9: Investigating FILESTREAM Databases, along with coverage of a few new systemwait types to deal with the various FILESTREAM-related operations and some of thecommon FILESTREAM metadata queries that you might find very helpful while workingwith FILESTREAM-enabled databases.293