数据库日志过大问题（转）

/* 本文由微软新闻组摘录下来的。一段非常有用的脚本。
如果碰到日志文件过大的问题，用SHIRNK DATABASE， TRUNCATE LOG FILE不是很有效时，可以考虑试下下面的脚本。把代码COPY到查询分析器里，然后修改其中的3个参数(数据库名，日志文件名，和目标日志文件的大小)，运行即可
*/
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SET NOCOUNT ON
DECLARE @LogicalFileName sysname,         --日志文件名
@MaxMinutes INT,                          --允许此脚本执行的最长时间
@NewSize INT --目标日志文件的大小


USE CRM                                   -- 要操作的数据库名

SELECT @LogicalFileName = 'CRM_LOG', -- 日志文件名

@MaxMinutes = 10, -- Limit on time allowed to wrap log.

@NewSize = 1 -- 想要收缩到的目标大小(单位M),此处标记收缩到1M

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