Shrink DB File by Increment to Target Free Space

Please start any new threads on our new site at https://forums.sqlteam.com. We've got lots of great SQL Server experts to answer whatever question you can come up with.

All Forums

General SQL Server Forums

Script Library

Shrink DB File by Increment to Target Free Space

Author

Topic

Michael Valentine Jones
Yak DBA Kernel (pronounced Colonel)

7020 Posts

Posted - 2007-03-09 : 19:45:01

This script can be used to shrink a database file in small increments until it reaches a target free space size.

It will loop to execute the DBCC SHRINKFILE command to shrink the database file by the desired increment until it reaches the target free space.

It is often better to shrink database files in small increments so that it can make continuous, incremental progress, instead of trying to shrink by a large amount in one command. This makes it easier to shrink a database that must be shrunk by a large amount, and makes it easier to interrupt without losing all progress.



-- Shrink_DB_File.sql
/*
This script is used to shrink a database file in
increments until it reaches a target free space limit.

Run this script in the database with the file to be shrunk.
1. Set @DBFileName to the name of database file to shrink.
2. Set @TargetFreeMB to the desired file free space in MB after shrink.
3. Set @ShrinkIncrementMB to the increment to shrink file by in MB
4. Run the script
*/

declare @DBFileName sysname
declare @TargetFreeMB int
declare @ShrinkIncrementMB int

-- Set Name of Database file to shrink
set @DBFileName = 'MyDatabaseFileName'

-- Set Desired file free space in MB after shrink
set @TargetFreeMB = 1000

-- Set Increment to shrink file by in MB
set @ShrinkIncrementMB = 50

-- Show Size, Space Used, Unused Space, and Name of all database files
select
	[FileSizeMB]	=
		convert(numeric(10,2),round(a.size/128.,2)),
	[UsedSpaceMB]	=
		convert(numeric(10,2),round(fileproperty( a.name,'SpaceUsed')/128.,2)) ,
	[UnusedSpaceMB]	=
		convert(numeric(10,2),round((a.size-fileproperty( a.name,'SpaceUsed'))/128.,2)) ,
	[DBFileName]	= a.name
from
	sysfiles a

declare @sql varchar(8000)
declare @SizeMB int
declare @UsedMB int

-- Get current file size in MB
select @SizeMB = size/128. from sysfiles where name = @DBFileName

-- Get current space used in MB
select @UsedMB = fileproperty( @DBFileName,'SpaceUsed')/128.

select [StartFileSize] = @SizeMB, [StartUsedSpace] = @UsedMB, [DBFileName] = @DBFileName

-- Loop until file at desired size
while  @SizeMB > @UsedMB+@TargetFreeMB+@ShrinkIncrementMB
	begin

	set @sql =
	'dbcc shrinkfile ( '+@DBFileName+', '+
	convert(varchar(20),@SizeMB-@ShrinkIncrementMB)+' ) '

	print 'Start ' + @sql
	print 'at '+convert(varchar(30),getdate(),121)

	exec ( @sql )

	print 'Done ' + @sql
	print 'at '+convert(varchar(30),getdate(),121)

	-- Get current file size in MB
	select @SizeMB = size/128. from sysfiles where name = @DBFileName
	
	-- Get current space used in MB
	select @UsedMB = fileproperty( @DBFileName,'SpaceUsed')/128.

	select [FileSize] = @SizeMB, [UsedSpace] = @UsedMB, [DBFileName] = @DBFileName

	end

select [EndFileSize] = @SizeMB, [EndUsedSpace] = @UsedMB, [DBFileName] = @DBFileName

-- Show Size, Space Used, Unused Space, and Name of all database files
select
	[FileSizeMB]	=
		convert(numeric(10,2),round(a.size/128.,2)),
	[UsedSpaceMB]	=
		convert(numeric(10,2),round(fileproperty( a.name,'SpaceUsed')/128.,2)) ,
	[UnusedSpaceMB]	=
		convert(numeric(10,2),round((a.size-fileproperty( a.name,'SpaceUsed'))/128.,2)) ,
	[DBFileName]	= a.name
from
	sysfiles a

CODO ERGO SUM

coolerbob
Aged Yak Warrior

841 Posts

Posted - 2008-11-21 : 09:48:50

Doesn't this make restores take longer because each shrink is re-run on restore?

Michael Valentine Jones
Yak DBA Kernel (pronounced Colonel)

7020 Posts

Posted - 2008-11-21 : 10:03:36

quote:
Originally posted by coolerbob

Doesn't this make restores take longer because each shrink is re-run on restore?

Only if you are applying transaction logs.

This isn't meant to be an everyday or routine thing to run. This is meant for situations where your database is much larger than necessary, and you want to remove a lot of space. Like if you have purged a lot of data and you want to shrink a database file from 100 GB to 30 GB.

Of course, when you get done you would want to de-fragment or re-index all the tables, because the shrink will cause a lot fragmentation.

CODO ERGO SUM

petemac
Starting Member

1 Post

Posted - 2011-10-14 : 07:55:57

Michael

I've ran your code but nothing seems to happen. This is the exact code I have run, suspect there is something I haven't changed. I'm not much of a programmer (understatement). I'd be grateful for your help.

Regards

PeteMac

-- Shrink_DB_File.sql
/*
This script is used to shrink a database file in
increments until it reaches a target free space limit.

Run this script in the database with the file to be shrunk.
1. Set @DBFileName to the name of database file to shrink.
2. Set @TargetFreeMB to the desired file free space in MB after shrink.
3. Set @ShrinkIncrementMB to the increment to shrink file by in MB
4. Run the script
*/

declare @DBFileName sysname
declare @TargetFreeMB int
declare @ShrinkIncrementMB int

-- Set Name of Database file to shrink
set @DBFileName = 'Test'

-- Set Desired file free space in MB after shrink
set @TargetFreeMB = 1000

-- Set Increment to shrink file by in MB
set @ShrinkIncrementMB = 50

-- Show Size, Space Used, Unused Space, and Name of all database files
select
[FileSizeMB] =
convert(numeric(10,2),round(a.size/128.,2)),
[UsedSpaceMB] =
convert(numeric(10,2),round(fileproperty( a.name,'SpaceUsed')/128.,2)) ,
[UnusedSpaceMB] =
convert(numeric(10,2),round((a.size-fileproperty( a.name,'SpaceUsed'))/128.,2)) ,
[DBFileName] = a.name
from
sysfiles a

declare @sql varchar(8000)
declare @SizeMB int
declare @UsedMB int

-- Get current file size in MB
select @SizeMB = size/128. from sysfiles where name = @DBFileName

-- Get current space used in MB
select @UsedMB = fileproperty( @DBFileName,'SpaceUsed')/128.

select [StartFileSize] = @SizeMB, [StartUsedSpace] = @UsedMB, [DBFileName] = @DBFileName

-- Loop until file at desired size
while @SizeMB > @UsedMB+@TargetFreeMB+@ShrinkIncrementMB
begin

set @sql =
'dbcc shrinkfile ( '+@DBFileName+', '+
convert(varchar(20),@SizeMB-@ShrinkIncrementMB)+' ) '

print 'Start ' + @sql
print 'at '+convert(varchar(30),getdate(),121)

exec ( @sql )

print 'Done ' + @sql
print 'at '+convert(varchar(30),getdate(),121)

-- Get current file size in MB
select @SizeMB = size/128. from sysfiles where name = @DBFileName

-- Get current space used in MB
select @UsedMB = fileproperty( @DBFileName,'SpaceUsed')/128.

select [FileSize] = @SizeMB, [UsedSpace] = @UsedMB, [DBFileName] = @DBFileName

end

select [EndFileSize] = @SizeMB, [EndUsedSpace] = @UsedMB, [DBFileName] = @DBFileName

-- Show Size, Space Used, Unused Space, and Name of all database files
select
[FileSizeMB] =
convert(numeric(10,2),round(a.size/128.,2)),
[UsedSpaceMB] =
convert(numeric(10,2),round(fileproperty( a.name,'SpaceUsed')/128.,2)) ,
[UnusedSpaceMB] =
convert(numeric(10,2),round((a.size-fileproperty( a.name,'SpaceUsed'))/128.,2)) ,
[DBFileName] = a.name
from
sysfiles a

MrTexasFreedom
Starting Member

13 Posts

Posted - 2011-12-13 : 20:22:36

Can someone comment on the parameters I'd need to use on a micro-shrink of a database as described by these stats (numbers in MB)?

This DB is taking up a lot of space and our datacenter is whomping us with disk space fees. I can't take the DB offline at all, but in the evenings, I don't have to worry about impacting the performance and I can rebuild indexes then.

All thoughts and suggestions appreciated!

mtf

quote:
Originally posted by Michael Valentine Jones

This script can be used to shrink a database file in small increments until it reaches a target free space size.

It will loop to execute the DBCC SHRINKFILE command to shrink the database file by the desired increment until it reaches the target free space.

CODO ERGO SUM

Kristen
Test

22859 Posts

Posted - 2011-12-14 : 08:38:39

I doubt you have a problem that Micro Shrink will solve. Please post this as a new topic in the relevant forum (e.g. http://www.sqlteam.com/forums/forum.asp?FORUM_ID=41 for "SQL 2008 Administration") and folk will no doubt have suggestions

pavelcc
Starting Member

2 Posts

Posted - 2018-02-22 : 13:20:01

This can solve your problem.
Create a SP based on the above statement in master db. Then, mark the sp a system sp
EXEC sp_ms_marksystemobject 'shrink_incremently'

then you can call the sp from any db using

use databasename
go
exec 'shrink_incremently'

Enjoy...
---------------------------------------------------
use master
go
create proc shrink_incremently
as
-- EXEC sp_ms_marksystemobject 'shrink_incremently'

-- Shrink_DB_File.sql
/*
This script is used to shrink a database file in
increments until it reaches a target free space limit.

Run this script in the database with the file to be shrunk.
1. Set @DBFileName to the name of database file to shrink.
2. Set @TargetFreeMB to the desired file free space in MB after shrink.
3. Set @ShrinkIncrementMB to the increment to shrink file by in MB
4. Run the script
*/

declare @DBFileName sysname
declare @TargetFreeMB int
declare @ShrinkIncrementMB int
declare @dbname varchar(100)

select @dbname = db_name()

-----------------------------------------------

select @DBFileName = name from master.sys.master_files
where database_id = (select dbid from master.dbo.sysdatabases where name = @dbname and file_id = 1)

-----------------------------------------------------
-- Set Name of Database file to shrink
--set @DBFileName = 'EDRI'

-- Set Desired file free space in MB after shrink
set @TargetFreeMB = 1000

-- Set Increment to shrink file by in MB
set @ShrinkIncrementMB = 50

-- Show Size, Space Used, Unused Space, and Name of all database files
select
[FileSizeMB] =
convert(numeric(10,2),round(a.size/128.,2)),
[UsedSpaceMB] =
convert(numeric(10,2),round(fileproperty( a.name,'SpaceUsed')/128.,2)) ,
[UnusedSpaceMB] =
convert(numeric(10,2),round((a.size-fileproperty( a.name,'SpaceUsed'))/128.,2)) ,
[DBFileName] = a.name
from
sysfiles a

declare @sql varchar(8000)
declare @SizeMB int
declare @UsedMB int

-- Get current file size in MB
select @SizeMB = size/128 from sysfiles where name = @DBFileName

--select * from sysfiles where name = 'EDRI__DEV'

-- Get current space used in MB
select @UsedMB = fileproperty( @DBFileName,'SpaceUsed')/128.

select [StartFileSize] = @SizeMB, [StartUsedSpace] = @UsedMB, [DBFileName] = @DBFileName

-- Loop until file at desired size
while @SizeMB > @UsedMB+@TargetFreeMB+@ShrinkIncrementMB
begin

set @sql =
'dbcc shrinkfile ( '+@DBFileName+', '+
convert(varchar(20),@SizeMB-@ShrinkIncrementMB)+' ) '

print 'Start ' + @sql
print 'at '+convert(varchar(30),getdate(),121)

exec ( @sql )

print 'Done ' + @sql
print 'at '+convert(varchar(30),getdate(),121)

-- Get current file size in MB
select @SizeMB = size/128. from sysfiles where name = @DBFileName

-- Get current space used in MB
select @UsedMB = fileproperty( @DBFileName,'SpaceUsed')/128.

select [FileSize] = @SizeMB, [UsedSpace] = @UsedMB, [DBFileName] = @DBFileName

end

select [EndFileSize] = @SizeMB, [EndUsedSpace] = @UsedMB, [DBFileName] = @DBFileName

-- Show Size, Space Used, Unused Space, and Name of all database files
select
[FileSizeMB] =
convert(numeric(10,2),round(a.size/128.,2)),
[UsedSpaceMB] =
convert(numeric(10,2),round(fileproperty( a.name,'SpaceUsed')/128.,2)) ,
[UnusedSpaceMB] =
convert(numeric(10,2),round((a.size-fileproperty( a.name,'SpaceUsed'))/128.,2)) ,
[DBFileName] = a.name
from
sysfiles a

---------------------------
--Life is Good
----------------------------

Subscribe to SQLTeam.com

SQLTeam.com Articles via RSS

SQLTeam.com Weblog via RSS

- Advertisement -

Resources