Summary

Each Microsoft SQL Server database is composed of at least two files, one with an .mdf extension and one with an .ldf extension. The file with the .ldf extension is the database's transaction log. The transaction log is a record of all modifications performed on a database. In case of a system failure, the transaction log can be used in conjunction with an up-to-date database backup to restore a system to a particular point in time.

More Information

In certain situations, the transaction log can grow at an unexpectedly fast pace and quickly consume more disk space than desired. By default, the recovery model for your SQL Server database may be the "Full recovery model." Without regular backups, the "Full recovery model" can cause the transaction log to grow to a very large size.

Unless you need the ability to recover your database to an exact point of failure, change the recovery model for your SQL Server database to use the "Simple recovery model" and use the DBCC SHRINKFILE T-SQL statement to shrink the transaction log.

Related Links

For more detailed explanations on possible causes of unexpected growth of the transaction log and on how to truncate and shrink your database's transaction log, please see the following Microsoft Knowledge Base articles:

873235 How to stop the transaction log of a SQL Server database from growing unexpectedly

907511 How to use the DBCC SHRINKFILE statement to shrink the transaction log file in SQL Server 2005

110139 INF: Causes of SQL Transaction Log Filling Up.

317375 INF: Transaction Log Grows Unexpectedly or Becomes Full on SQL Server.

272318 INF: Shrinking the Transaction Log in SQL Server 2000 with DBCC SHRINKFILE.