在上一篇文章中介绍了如何删除数据库日志文件，但是想想还是不是不方便需要手工操作，于是想结合作业实现自动清理日志文件，在清理日志文件时我加上了条件，当磁盘控空间不足多少M才会清理，下面介绍如何实现该功能。没有阅读上一篇文章的，可以通过传送门阅读(删除数据库日志文件的方法)！

阅读目录

• SQL查询磁盘空间大小
• 存储过程添加作业
• 示例下载

exec master..xp_fixeddrives

GO
IF EXISTS(SELECT 1 FROM sysobjects WHERE id=OBJECT_ID('usp_p_CreateJob'))
BEGINDROP PROC dbo.usp_p_CreateJob
END
GO
CREATE PROCEDURE dbo.usp_p_CreateJob(@jobname varchar(100),         @sql VARCHAR(MAX),                      @freqtype varchar(6)='day',     @fsinterval int=1,                @time int=235959,                     @description VARCHAR(1000)=''
)
AS
/*
功能：创建SQL作业
参数：@jobname:作业名称@sql:要执行的命令@freqtype:时间周期,month 月,week 周,day 日@fsinterval:相对于每日的重复次数@time:开始执行时间,对于重复执行的作业,将从0点到23:59分@description:作业的描述
*/
BEGINDECLARE @dbname AS VARCHAR(500)SET @dbname=DB_NAME()BEGIN TRANSACTIONDECLARE @ReturnCode INTSELECT @ReturnCode = 0--添加类别IF NOT EXISTS (SELECT name FROM msdb.dbo.syscategories WHERE name='添加作业' AND category_class=1)BEGINEXEC @ReturnCode = msdb.dbo.sp_add_category @class=N'JOB', @type=N'LOCAL', @name=N'添加作业'IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollbackEND--删除作业  DECLARE @JobID BINARY(16)   DECLARE @ErrMsg NVARCHAR(500)      SELECT  @JobID = job_id  FROM msdb.dbo.sysjobs WHERE name = @JobName  IF ( @JobID IS NOT NULL )  BEGIN   -- 检查此作业是否为多重服务器作业  IF ( EXISTS ( SELECT * FROM msdb.dbo.sysjobservers WHERE ( job_id = @JobID ) AND ( server_id <> 0 ) ) )  BEGIN  --多重服务器作业不操作  SET @ErrMsg = '无法导入作业"' + @JobName + '"，因为已经有相同名称的多重服务器作业。'  RAISERROR (@ErrMsg, 16, 1)   GOTO QuitWithRollback  END  ELSE  BEGIN  -- 删除［本地］作业   EXECUTE msdb.dbo.sp_delete_job @job_name = @JobName  SELECT @JobID = NULL  END  END  SET @JobID = NULL    EXEC @ReturnCode =  msdb.dbo.sp_add_job @job_name=@jobname, @enabled=1, @notify_level_eventlog=2, @notify_level_email=0, @notify_level_netsend=0, @notify_level_page=0, @delete_level=0, @description=@description, @category_name=N'添加作业', @owner_login_name=N'sa', @job_id = @jobId OUTPUTIF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollback/****** Object:  Step [数据同步]    Script Date: 01/25/2014 23:00:36 ******/EXEC @ReturnCode = msdb.dbo.sp_add_jobstep @job_id=@jobId, @step_name=@jobname, @step_id=1, @cmdexec_success_code=0, @on_success_action=1, @on_success_step_id=0, @on_fail_action=2, @on_fail_step_id=0, @retry_attempts=5, @retry_interval=5, @os_run_priority=0, @subsystem=N'TSQL', @command= @sql, @database_name=@dbname, @flags=0IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollbackEXEC @ReturnCode = msdb.dbo.sp_update_job @job_id = @jobId, @start_step_id = 1IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollback--创建调度declare @ftype int,@fstype int,@ffactor intselect @ftype=case @freqtype when 'day' then 4when 'week' then 8when 'month' then 16 end,@fstype=case @fsinterval when 1 then 0 else 8 endif @fsinterval<>1 set @time=0set @ffactor=case @freqtype when 'day' then 0 else 1 endEXEC msdb..sp_add_jobschedule @job_name=@jobname, @name = @jobname,@freq_type=@ftype ,                                        @freq_interval=1,                                       @freq_subday_type=@fstype,                       @freq_subday_interval=@fsinterval,        @freq_recurrence_factor=@ffactor,@active_start_time=@time                         IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollbackEXEC @ReturnCode = msdb.dbo.sp_add_jobserver @job_id = @jobId, @server_name = N'(local)'IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollbackCOMMIT TRANSACTIONGOTO EndSaveQuitWithRollback:IF (@@TRANCOUNT > 0) ROLLBACK TRANSACTIONEndSave:
END
GO

GO
IF EXISTS(SELECT 1 FROM sysobjects WHERE id=OBJECT_ID('usp_p_delDBLog'))
BEGINDROP PROC dbo.usp_p_delDBLog
END
GO
CREATE PROC usp_p_delDBLog(@DriveLimit AS BIGINT,@DBLogSise AS INT =0
)
/*
*    功能：收缩当前数据库日志文件
*    参数  @DriveLimit:当前数据库所在磁盘空间到达多少的时候进行收缩数据库  MB
*          @DBLogSise：日志文件收缩至多少M 默认收缩到最小
*/
AS
BEGINIF @DBLogSise<0 OR @DriveLimit<0BEGINRETURNEND--当前数据库所在磁盘DECLARE @Drive AS VARCHAR(10)DECLARE @Available AS BIGINTSELECT TOP 1  @Drive=SUBSTRING(filename,1,1)  from   sysfilesCREATE TABLE #TempFile(Drive VARCHAR(10),--磁盘Available BIGINT --可用大小MB
    )INSERT INTO #TempFile(Drive,Available)exec master..xp_fixeddrives--查询当前数据库所在磁盘剩余空间大小SELECT @Available=Available FROM #TempFileWHERE Drive=@Drive--符合条件则进行收缩日志文件IF @Available<=@DriveLimitBEGIN--查询出数据库对应的日志文件名称DECLARE @strDBName AS NVARCHAR(500)DECLARE @strLogName AS NVARCHAR(500)DECLARE @strSQL AS VARCHAR(1000)SELECT @strLogName=B.name,@strDBName=A.nameFROM master.sys.databases AS AINNER JOIN sys.master_files AS BON A.database_id = B.database_idWHERE A.database_id=DB_ID() SET @strSQL='--设置数据库恢复模式为简单ALTER DATABASE ['+@strDBName+'] SET RECOVERY SIMPLE;--收缩日志文件DBCC SHRINKFILE ('''+@strLogName+''' , '+CONVERT(VARCHAR(20),@DBLogSise)+');--恢复数据库还原模式为完整ALTER DATABASE ['+@strDBName+'] SET RECOVERY FULL 'exec(@strSQL)    ENDDROP TABLE #TempFile
END
GO

    --当前数据库所在磁盘DECLARE @Drive AS VARCHAR(10)DECLARE @Available AS BIGINTSELECT TOP 1  @Drive=SUBSTRING(filename,1,1)  from   sysfilesCREATE TABLE #TempFile(Drive VARCHAR(10),--磁盘Available BIGINT --可用大小MB
    )INSERT INTO #TempFile(Drive,Available)exec master..xp_fixeddrives--查询当前数据库所在磁盘剩余空间大小SELECT @Available=Available FROM #TempFileWHERE Drive=@Drive

--添加作业
--作业每天间隔两小时执行一次
--执行条件为磁盘空间不足 5000MB，即@DriveLimit=5000 可自行配置
DECLARE @@jobname AS VARCHAR(1000)
SELECT @@jobname=DB_NAME()+'_自动清理当前数据库日志文件'
EXEC dbo.usp_p_CreateJob @jobname = @@jobname, -- varchar(100)@sql = 'EXEC usp_p_delDBLog @DriveLimit=5000,@DBLogSise=0', -- varchar(max)@freqtype = 'day', -- varchar(6)@fsinterval = 2, -- int@time = 235959, -- int@description = '自动清理当前数据库日志文件' -- varchar(1000)