This document describes how to shrink a SQL Server database to recover unused space. It can be done through SQL Server Management Studio or Transact-SQL. Shrinking moves data pages towards the front of files and frees up space at the end, which is then returned to the file system. Limitations include that databases cannot shrink below their minimum size and backups cannot occur during shrinking. It is recommended to only shrink after operations that create unused space and to rebuild indexes afterwards due to increased fragmentation.

1. Shrink a Database
SQL Server 2016
Other Versions
Applies To: SQL Server 2016
This topic describes how to shrink a database by using Object in SQL Server 2016 by using SQL Server
Management Studio or Transact-SQL.
Shrinking data files recovers space by moving pages of data from the end of the file to unoccupied space
closer to the front of the file. When enough free space is created at the end of the file, data pages at end
of the file can be deallocated and returned to the file system.
In This Topic
 Before you begin:
Limitations and Restrictions
Recommendations
Security
 To shrink a database, using:
SQL Server Management Studio
Transact-SQL
 Follow Up: You shrink a database
Before You Begin
Limitations and Restrictions
 The database cannot be made smaller than the minimum size of the database. The minimum size
is the size specified when the database was originally created, or the last explicit size set by using
a file-size-changing operation, such as DBCC SHRINKFILE. For example, if a database was
originally created with a size of 10 MB and grew to 100 MB, the smallest size the database could
be reduced to is 10 MB, even if all the data in the database has been deleted.
 You cannot shrink a database while the database is being backed up. Conversely, you cannot
backup a database while a shrink operation on the database is in process.
 DBCC SHRINKDATABASE will fail when it encounters an xVelocity memory optimized columnstore
index. Work completed before encountering the columnstore index will succeed so the database
might be smaller. To complete DBCC SHRINKDATABASE, disable all columnstore indexes before
executing DBCC SHRINKDATABASE, and then rebuild the columnstore indexes.
Recommendations
 To view the current amount of free (unallocated) space in the database. For more information,
see Display Data and Log Space Information for a Database
 Consider the following information when you plan to shrink a database:
o A shrink operation is most effective after an operation that creates lots of unused space,
such as a truncate table or a drop table operation.
o Most databases require some free space to be available for regular day-to-day
operations. If you shrink a database repeatedly and notice that the database size grows
again, this indicates that the space that was shrunk is required for regular operations. In
these cases, repeatedly shrinking the database is a wasted operation.

2. o A shrink operation does not preserve the fragmentation state of indexes in the database,
and generally increases fragmentation to a degree. This is another reason not to
repeatedly shrink the database.
o Unless you have a specific requirement, do not set the AUTO_SHRINK database option to
ON.
Security
Permissions
Requires membership in the sysadmin fixed server role or the db_owner fixed database role.
Using SQL Server Management Studio
To shrink a database
1. In Object Explorer, connect to an instance of the SQL Server Database Engine, and then expand
that instance.
2. Expand Databases, and then right-click the database that you want to shrink.
3. Point to Tasks, point to Shrink, and then click Database.
Database
Displays the name of the selected database.
Current allocated space
Displays the total used and unused space for the selected database.
Available free space
Displays the sum of free space in the log and data files of the selected database.
Reorganize files before releasing unused space
Selecting this option is equivalent to executing DBCC SHRINKDATABASE specifying a target
percent option. Clearing this option is equivalent to executing DBCC SHRINKDATABASE with
TRUNCATEONLY option. By default, this option is not selected when the dialog is opened. If this
option is selected, the user must specify a target percent option.
Maximum free space in files after shrinking
Enter the maximum percentage of free space to be left in the database files after the database has
been shrunk. Permissible values are between 0 and 99.
4. Click OK.
Using Transact-SQL
To shrink a database
1. Connect to the Database Engine.
2. From the Standard bar, click New Query.
3. Copy and paste the following example into the query window and click Execute. This example
uses DBCC SHRINKDATABASE to decreases the size of the data and log files in
the UserDB database and to allow for 10 percent free space in the database.
Transact-SQL
DBCC SHRINKDATABASE (UserDB, 10);
GO
Follow Up: After you shrink a database
Data that is moved to shrink a file can be scattered to any available location in the file. This causes index
fragmentation and can slow the performance of queries that search a range of the index. To eliminate the
fragmentation, consider rebuilding the indexes on the file after shrinking.
See Also

3. Shrink a File
sys.databases (Transact-SQL)
sys.database_files (Transact-SQL)
DBCC (Transact-SQL)
DBCC SHRINKFILE (Transact-SQL)
Database Files and Filegroups