SET NOCOUNT ON
DECLARE @LogicalFileName sysname,
@MaxMinutes INT,
@NewSize INT

USE "abc"-- 要操作的数据库名
SELECT @LogicalFileName = ''''abc_log'''', -- 日志文件名
@MaxMinutes = 10, -- Limit on time allowed to wrap log.
@NewSize = 500 -- 你想设定的日志文件的大小(M)

-- Setup / initialize
DECLARE @OriginalSize int
SELECT @OriginalSize = size 
FROM sysfiles
WHERE name = @LogicalFileName
SELECT ''''Original Size of '''' + db_name() + '''' LOG is '''' + 
CONVERT(VARCHAR(30),@OriginalSize) + '''' 8K pages or '''' + 
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + ''''MB''''
FROM sysfiles
WHERE name = @LogicalFileName
CREATE TABLE DummyTrans
(DummyColumn char (8000) not null)

DECLARE @Counter INT,
@StartTime DATETIME,
@TruncLog VARCHAR(255)
SELECT @StartTime = GETDATE(),
@TruncLog = ''''BACKUP LOG '''' + db_name() + '''' WITH TRUNCATE_ONLY''''

DBCC SHRINKFILE (@LogicalFileName, @NewSize)
EXEC (@TruncLog)
-- Wrap the log if necessary.
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 
AND (@OriginalSize * 8 /1024) > @NewSize 
BEGIN -- Outer loop.
SELECT @Counter = 0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
BEGIN -- update
INSERT DummyTrans valueS (''''Fill Log'''') 
DELETE DummyTrans
SELECT @Counter = @Counter + 1
END 
EXEC (@TruncLog) 
END 
SELECT ''''Final Size of '''' + db_name() + '''' LOG is '''' +
CONVERT(VARCHAR(30),size) + '''' 8K pages or '''' + 
CONVERT(VARCHAR(30),(size*8/1024)) + ''''MB''''
FROM sysfiles 
WHERE name = @LogicalFileName
DROP TABLE DummyTrans
SET NOCOUNT OFF