SQL Server在删除数据后,会重新利用这部分空间,所以如果不是空间紧张的情况下,可以不回收。
回收一般先回收日志文件,因为这个回收速度非常快,可以短时间内清理出一部分可用空间。
回收步骤:
1、查看日志文件大小【一般回收比较大的】
--适用于RDS For SQL Server2012 SELECT DB_NAME(database_id) AS [Database Name],[Name] AS [Logical Name],[Physical_Name] AS [Physical Name],((size * 8) / 1024) AS [Size(MB)] FROM sys.master_files ORDER BY [Size(MB)] DESC --适用于RDS For SQL Server2008R2,需要对数据库逐个执行 USE 数据库名 GO SELECT a.name as 逻辑文件名, size/128 [totalspace文件大小(兆)], FILEPROPERTY(a.name, 'SpaceUsed')/128 [usedspace已用空间(兆)], size/128 - FILEPROPERTY(a.name, 'SpaceUsed')/128 [未用空间(兆)], FILEPROPERTY(a.name, 'SpaceUsed')*100.0/size [使用率(%)] FROM sys.database_files a cross join (select recovery_model_desc, log_reuse_wait,log_reuse_wait_desc,is_auto_shrink_on from sys.databases where name=DB_NAME())b WHERE type=1
2、查看日志文件空间是否可回收【只有log_reuse_wait_desc是NOTHING状态才可回收】
SELECT [name] ,[log_reuse_wait_desc] FROM master.sys.databases WHERE [name]='数据库名【第1步获取】'
3、回收日志文件空间
DBCC SHRINKFILE(logicalName【第1步获取】)
常见的日志等待类型是 LOG_BACKUP,日志还没有备份,所以不能截断 解决方案: ACTIVE_TRANSACTION,有活跃事务阻塞了日志截断 解决方案: 执行 DBCC OPENTRAN ,获取下长时间的活跃事务的SPID 然后执行 DBCC INPUTBUFFER(SPID) 查看下这个请求SQL,考虑是否可以kill阻塞源,kill后再查下log_reuse_wait,尝试shrink
4、查看数据文件大小
USE 数据库名 GO SELECT a.name as 逻辑文件名, size/128 [totalspace文件大小(兆)], FILEPROPERTY(a.name, 'SpaceUsed')/128 [usedspace已用空间(兆)], size/128 - FILEPROPERTY(a.name, 'SpaceUsed')/128 [未用空间(兆)], FILEPROPERTY(a.name, 'SpaceUsed')*100.0/size [使用率(%)] FROM sys.database_files a cross join (select recovery_model_desc, log_reuse_wait,log_reuse_wait_desc,is_auto_shrink_on from sys.databases where name=DB_NAME())b WHERE type=0
5、收缩数据文件【按照经验,最好每5G循环收缩,如果影响业务,随时中断,不会回滚】
declare @usedspace int ,@totalspace int select @usedspace= xxx,@totalspace =yyy while @totalspace> @usedspace begin set @totalspace= @totalspace-5 *1024 DBCC SHRINKFILE( 逻辑文件名,@totalspace ) end
注:逻辑文件名,usedspace,totalspace从第4步的结果集获取
6、查看收缩进度【预估值】
SELECT DB_NAME(database_id) as dbname, session_id, request_id, start_time , percent_complete , dateadd(mi ,estimated_completion_time/60000,getdate ()) as ETC FROM sys.dm_exec_requests where percent_complete<>0
--查询当前数据库备份进度 SELECT DB_NAME(er.[database_id]) [DatabaseName],er.[command] AS [CommandType],er.[percent_complete] ,er.start_time,CONVERT(DECIMAL(5, 2) , er.[percent_complete]) AS [Complete_Percent] ,CONVERT(DECIMAL(38, 2), er.[total_elapsed_time] / 60000.00) AS [ElapsedTime_m] ,CONVERT(DECIMAL(38, 2), er.[estimated_completion_time] / 60000.00) AS [EstimatedCompletionTime_m] FROM sys.dm_exec_requests AS er WHERE er.[command] in ( 'RESTORE DATABASE' ,'BACKUP DATABASE') --DB_NAME(er.[database_id]) in ('ky2011') and --查看数据库收缩进度 SELECT DB_NAME(er.[database_id]) [DatabaseName],er.[command] AS [CommandType],er.[percent_complete] ,er.start_time,CONVERT(DECIMAL(5, 2) , er.[percent_complete]) AS [Complete_Percent] ,CONVERT(DECIMAL(38, 2), er.[total_elapsed_time] / 60000.00) AS [ElapsedTime_m] ,CONVERT(DECIMAL(38, 2), er.[estimated_completion_time] / 60000.00) AS [EstimatedCompletionTime_m] FROM sys.dm_exec_requests as er WHERE command in ('DbccFilesCompact','AUTOSHRINK')
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