SQL Server查看索引重建、重組索引進度

相信不少SQL Server DBA或開發人員在重建或重組大表索引時，都會至關鬱悶，不知道索引重建的進度，這個對於DBA徹底是一個黑盒子，對於系統負載很是大的系統或維護窗口較短的系統，你會遇到一些挑戰。例如，你建立索引的時候，不少會話被阻塞，你只能取消建立索引的任務。查看這些索引維護操做的進度、預估時間對於咱們有較大的意義，須要根據這個作一些決策。下面咱們來看看看看如何獲取CREATE INDEX、ALTER INDEX REBUILD、ALTER INDEX ORGANIZE的進度。

 

 

索引重組

 

從SQL Server 2008開始，有個DMV視圖sys.dm_exec_requests，裏面有個字段percent_complete表示如下命令完成的工做的百分比，這裏面就包括索引重組（ALTER INDEX REORGANIZE），這其中不包括ALTER INDEX REBUILD，能夠查看索引重組（ALTER INDEX ORGANIZE）完成的百分比。也就是說在SQL Server 2008以前是沒法獲取索引重組的進度狀況的。

 

percent_complete

real

Percentage of work completed for the following commands: ALTER INDEX REORGANIZE AUTO_SHRINK option with ALTER DATABASE BACKUP DATABASE DBCC CHECKDB DBCC CHECKFILEGROUP DBCC CHECKTABLE DBCC INDEXDEFRAG DBCC SHRINKDATABASE DBCC SHRINKFILE RECOVERY RESTORE DATABASE ROLLBACK TDE ENCRYPTION Is not nullable.

 

 

測試環境：SQL Server 2008 、 2017 RTM CU13

 

SELECT  er.session_id ,

        er.blocking_session_id ,

        er.status ,

        er.command ,

        DB_NAME(er.database_id) DB_name ,

        er.wait_type ,

        et.text SQLText ,

        er.percent_complete

FROM    sys.dm_exec_requests er

        CROSS APPLY sys.dm_exec_sql_text(er.sql_handle) et

WHERE   er.session_id = 57

        AND er.session_id <> @@SPID;

 

 

 

 

 

 

 

索引重建

 

上面DMV視圖sys.dm_exec_requests是否也能夠查看索引重建的進度呢? 答案是不行，測試發現percent_complete這個進度一直爲0，那麼要如何查看索引重建（INDEX REBUILD）的進度呢？

 

不過自SQL Server 2014開始，SQL Server提供了一個新特性：sys.dm_exec_query_profiles，它能夠實時監控正在執行的查詢的進度狀況（Monitors real time query progress while the query is in execution）。固然，須要啓用實時查詢監控才行。通常只需啓用會話級別的實時查詢監控，能夠經過啓用SET STATISTICS XML ON; 或SET STATISTICS PROFILE ON;開啓。而從SQL Server 2016 (13.x)SP1 開始，您能夠或者開啓跟蹤標誌 7412或使用 query_thread_profile 擴展的事件。下面是官方文檔的描述：

 

In SQL Server 2014 (12.x) SP2 and later use SET STATISTICS PROFILE ON or SET STATISTICS XML ON together with the query under investigation. This enables the profiling infrastructure and produces results in the DMV for the session where the SET command was executed. If you are investigating a query running from an application and cannot enable SET options with it, you can create an Extended Event using the query_post_execution_showplan event which will turn on the profiling infrastructure.

In SQL Server 2016 (13.x) SP1, you can either turn on trace flag 7412 or use the query_thread_profile extended event.

 

 

--Configure query for profiling with sys.dm_exec_query_profiles 

SET STATISTICS PROFILE ON; 

GO 

 

--Or enable query profiling globally under SQL Server 2016 SP1 or above 

DBCC TRACEON (7412, -1); 

GO

 

ALTER INDEX Your_Index_Name ON Your_Table_Name REBUILD;

GO

 

 

 

 

DECLARE @SPID INT = 53;

;WITH agg AS

(

     SELECT SUM(qp.[row_count]) AS [RowsProcessed],

            SUM(qp.[estimate_row_count]) AS [TotalRows],

            MAX(qp.last_active_time) - MIN(qp.first_active_time) AS [ElapsedMS],

            MAX(IIF(qp.[close_time] = 0 AND qp.[first_row_time] > 0,

                    [physical_operator_name],

                    N'<Transition>')) AS [CurrentStep]

     FROM sys.dm_exec_query_profiles qp

     WHERE qp.[physical_operator_name] IN (N'Table Scan', N'Clustered Index Scan', N'Sort' , N'Index Scan')

     AND   qp.[session_id] = @SPID

), comp AS

(

     SELECT *,

            ([TotalRows] - [RowsProcessed]) AS [RowsLeft],

            ([ElapsedMS] / 1000.0) AS [ElapsedSeconds]

     FROM   agg

)

SELECT [CurrentStep],

       [TotalRows],

       [RowsProcessed],

       [RowsLeft],

       CONVERT(DECIMAL(5, 2),

               (([RowsProcessed] * 1.0) / [TotalRows]) * 100) AS [PercentComplete],

       [ElapsedSeconds],

       (([ElapsedSeconds] / [RowsProcessed]) * [RowsLeft]) AS [EstimatedSecondsLeft],

       DATEADD(SECOND,

               (([ElapsedSeconds] / [RowsProcessed]) * [RowsLeft]),

               GETDATE()) AS [EstimatedCompletionTime]

FROM   comp;

 

 

 

 

注意事項：在SQL Server 2016 SP1以前，若是要使用sys.dm_exec_query_profiles查看索引重建的進度，那麼就必須在索引重建以前設置SET STATISTICS PROFILE ON or SET STATISTICS XML ON。 而自

SQL Server 2016 SP1以後，可使用DBCC TRACEON (7412, -1);開啓全局會話的跟蹤標記，或者開啓某個會話的跟蹤標記，固然若是要使用sys.dm_exec_query_profiles查看索引重建的進度，也必須開啓7412跟蹤標記

，而後重建索引，不然也沒有值。

 

注意事項：：索引重組時，sys.dm_exec_query_profiles中沒有數據。因此sys.dm_exec_query_profiles不能用來查看索引重組的進度。

 

 

新建索引

 

新建索引進度的查詢，也可使用下面SQL語句。這裏不作展開。

 

DECLARE @SPID INT = 56;

;WITH agg AS

(

     SELECT SUM(qp.[row_count]) AS [RowsProcessed],

            SUM(qp.[estimate_row_count]) AS [TotalRows],

            MAX(qp.last_active_time) - MIN(qp.first_active_time) AS [ElapsedMS],

            MAX(IIF(qp.[close_time] = 0 AND qp.[first_row_time] > 0,

                    [physical_operator_name],

                    N'<Transition>')) AS [CurrentStep]

     FROM sys.dm_exec_query_profiles qp

     WHERE qp.[physical_operator_name] IN (N'Table Scan', N'Clustered Index Scan', N'Sort' , N'Index Scan')

     AND 

       qp.[session_id] = @SPID

), comp AS

(

     SELECT *,

            ([TotalRows] - [RowsProcessed]) AS [RowsLeft],

            ([ElapsedMS] / 1000.0) AS [ElapsedSeconds]

     FROM   agg

)

SELECT [CurrentStep],

       [TotalRows],

       [RowsProcessed],

       [RowsLeft],

       CONVERT(DECIMAL(5, 2),

               (([RowsProcessed] * 1.0) / [TotalRows]) * 100) AS [PercentComplete],

       [ElapsedSeconds],

       (([ElapsedSeconds] / [RowsProcessed]) * [RowsLeft]) AS [EstimatedSecondsLeft],

       DATEADD(SECOND,

               (([ElapsedSeconds] / [RowsProcessed]) * [RowsLeft]),

               GETDATE()) AS [EstimatedCompletionTime]

FROM   comp;

SELECT   

       node_id,

       physical_operator_name, 

       SUM(row_count) row_count, 

       SUM(estimate_row_count) AS estimate_row_count,

       CAST(SUM(row_count)*100 AS float)/SUM(estimate_row_count)  as estimate_percent_complete

FROM sys.dm_exec_query_profiles   

WHERE session_id=@SPID  

GROUP BY node_id,physical_operator_name  

ORDER BY node_id desc;

 

參考資料：

 

https://docs.microsoft.com/zh-cn/sql/relational-databases/system-dynamic-management-views/sys-dm-exec-query-profiles-transact-sql?view=sql-server-2017

https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-exec-requests-transact-sql?view=sql-server-2017

https://dba.stackexchange.com/questions/139191/sql-server-how-to-track-progress-of-create-index-command

https://support.microsoft.com/zh-cn/help/4053291/fix-sys-dm-exec-query-profiles-dmv-returns-wrong-estimate-row-count-in

https://blogs.msdn.microsoft.com/sql_pfe_blog/2016/12/22/create-index-monitoring-progress/