FILESTREAM files being left behind after row deleted

sp_filestream_force_garbage_collection
sql server filestream location
file handling in sql server
enable filestream sql server 2012
storing files in sql server

I have successfully set up FILESTREAM on my SQL 2008 server; however I've noticed that even when I have deleted rows containing FILESTREAM data, the physical data file doesn't seem to get deleted.

By the physical file, I mean the file in SQLServer's managed directory with a uniqueidentifer as the filename not the original file added to the dbase.

Does anyone know if SQLServer will delete the file eventually? If there are a lot of large files removed from the dbase I'd expect to be able to reclaim the space quickly that's all.

FILESTREAM data is subject to transaction control and therefore is not deleted instantly.

Instead, SQL Server runs a garbage collector which purges the old data when it is sure it had been ultimately deleted.

From the documentation:

FILESTREAM garbage collection is a background task that is triggered by the database checkpoint process. A checkpoint is automatically run when enough transaction log has been generated. For more information, see the SQL Server 2008 Books Online topic "CHECKPOINT and the Active Portion of the Log" (http://msdn.microsoft.com/en-us/library/ms189573.aspx). Given that FILESTREAM file operations are minimally logged in the database’s transaction log, it may take a while before the number of transaction log records generated triggers a checkpoint process and garbage collection occurs. If this becomes a problem, you can force garbage collection by using the CHECKPOINTstatement.

FILESTREAM files not deleted - MSDN, My free space is low even if I delete all rows on some tables. Usually the FILESTREAM data is not deleted immediately from file system is a background task that is triggered by the database checkpoint process. A checkpoint is automatically run when enough transaction log has been generated. FILESTREAM les données sont soumises au contrôle des transactions et ne sont donc pas supprimées instantanément.. au Lieu de cela, SQL Server exécute un collecteur d'ordures qui purge les vieilles données quand il est sûr qu'il a été finalement supprimé.

use

sp_filestream_force_garbage_collection

unfortunately this only works >= SQL Server 2012

Microsoft SQL Server 2012 Internals: Micro SQL Serve 2012 Int_p1, In the left pane, you can see the two FILESTREAM containers, The operating system file structure after inserting FILESTREAM data. are always performed as a DELETE followed by an INSERT, so you see a new row in the directory for the  A FILESTREAM container cannot be removed until all the deleted files within it have been cleaned up by the garbage collector. The FILESTREAM garbage collector runs automatically. However, if you need to remove a container before the garbage collector has run, you can use sp_filestream_force_garbage_collection to run the garbage collector manually.

First you have to create a Checkpoint for the Garbage Collector work. After you Deleted rows you can run this code to eliminate all files that don't belong to any row.

USE [DataBaseName]
GO

-- Create a checkpoint on current database
CHECKPOINT
GO 

-- Execute Garbage Collector after a checkpoint created
EXEC sp_filestream_force_garbage_collection  'DataBaseName'
GO

Microsoft SQL Server 2008 Internals, Every row that has a nonNULL value in a FILESTREAM column has a file, Figure 75 shows you what your file system would look like after running the In the left pane, you can see the two filestream containers (filestream1 and filestream2). DELETE followed by an INSERT, so you see a new row in the directory for the  Usually the FILESTREAM data is not deleted immediately from file system because SQL Server transaction logging under full and bulk recovery models permit the crash recovery.Please try to change it to simple recovery model. And FILESTREAM garbage collection is a background task that is triggered by the database checkpoint process.

DELETE FROM tbl_XXX DECLARE @test CHECKPOINT @test = 0

Run this in your sql server and You can observe the file getting deleted from file system also..

You can set the the number of minutes or seconds to wait for the garbage collector to clean up the files from filesystem after performing the deletion operation.

Thanks

haranath

How is FileStream Cleanup Done?, When I delete 1000 rows the folder size of the physical location does Same for updating the filestream column by setting it to null, files that sql server created and now that all the rows are deleted, Hi, So, being complicated??? the binary data lives on the filesystem instead of inside the database. 1.Remove the FILESTREAM attribute from columns and tables. You'll need to move data to a new column. ALTER TABLE MyTable ADD FileData varbinary(max) NULL; GO update MyTable set FileData = FileStreamData GO ALTER TABLE MyTable DROP column FileStreamData GO ALTER TABLE MyTable SET (FILESTREAM_ON="NULL") GO EXEC sp_RENAME 'MyTable', 'FileStreamData', 'COLUMN' GO

SQL Server 2008 Transact-SQL Recipes: A Problem-Solution Approach, I have successfully set up FILESTREAM on my SQL 2008 server; however I've noticed that even when I have deleted rows containing FILESTREAM data, the  Even though the record has been deleted from tables, the file will be available in the FILSTREAM data store physically. It will be deleted by Garbage Collector. Garbage Collector process executes when the checkpoint event occurs. By giving an explicit checkpoint, you can delete it immediately after deleting from the table. Query to delete Files from SQL Table:

Pro Full-Text Search in SQL Server 2008, COMMIT TRAN If I wish to delete the file, I can set the column value to NULL: In this recipe, I started off by checking whether FILESTREAM was enabled on the Had I left off the FILESTREAM attribute, any varbinary data stored would have been Next, I inserted a new row into the table that held the BMP file of the SQL​  Accessing filestream files as regular files is not something that's recommended. By default you won't even have access to these files. It's like asking where in an mdf file you can find the value you just inserted in a database table. Tampering with filestream files directly (rather than via the provided API) is an easy way to corrupt the database.

SQL Server FILESTREAM Database Corruption and Remediation, for us to be here dedicated to the great task remaining before us— that from these of DML action against a FILESTREAM-enabled column When you delete a row value of the column to NULL, the underlying file in the file system is deleted. When a FILESTREAM field is set to NULL, the BLOB data associated with the field is deleted. You cannot use a Transact-SQL chunked update, implemented as UPDATE**.**Write(), to perform partial updates to the data.

Comments
  • FYI - This is only for SQL 2012
  • Yes thanks. I also need that. One good reason to upgrade to 2012!
  • I tried this on my local SQL Server 2012 Express and it doesn't seem to work.
  • if you want this to start working immediatly, call it twice, it will then start removing files in the background. can take a long while depending of the number of files
  • @corix010 If it doesn't work check the recovery mode of your DB. If it is full, change it to Simple and then run the command again. It will work
  • easier: DELETE FROM table CHECKPOINT
  • @DanDan I know this is like years ago but I just want to warn other users about the danger of accidentally deleting all rows in your table when DELETE FROM table CHECKPOINT command is used. I tried it and it deleted all rows in my table. Fortunately my table just contains sample data.