清除,收缩或截断数据库日志

DBCC SHRINKFILE (@LogicalFileName, @NewSize)

再是
BACKUP LOG dbname WITH TRUNCATE_ONLY



或者，先设置数据库为简单恢复模式，再收缩文件，然后再设置数据库为完整恢复模式。（要是数据库原来就是简单恢复模式，就直接收缩文件即可）
e.g:

USE AdventureWorks;
GO
-- Truncate the log by changing the database recovery model to SIMPLE.
ALTER DATABASE AdventureWorks
SET RECOVERY SIMPLE;
GO
-- Shrink the truncated log file to 1 MB.
DBCC SHRINKFILE (AdventureWorks_Log, 1);
GO
-- Reset the database recovery model.
ALTER DATABASE AdventureWorks
SET RECOVERY FULL;
GO
要是截断日志，可以这样：
BACKUP LOG dbname WITH NO_LOG
Dbcc Shrinkdatabase('dbname')