Question

我有这个更新远程表的sql update语句。有什么办法可以优化/加速这段代码吗？它作为存储过程的一部分运行。

DECLARE @WIP Table(Item varchar(25), WIP int)

--Get Work In Progress Numbers
INSERT INTO @WIP
select (UPC.ItemPrefix + '-' + UPC.ItemCode) As Item, SUM(PO.Quantity) As WIP
--into #WIP
from [NCLGS].[dbo].[AL_ItemUPCs] UPC
INNER JOIN al_PO PO ON PO.UPCID = UPC.UPCID
where PO.status in ('Assigned', 'New', 'UnAssigned', 'WaitingForFile')
Group by  (UPC.ItemPrefix + '-' + UPC.ItemCode)

--SLOW PART, takes over 17 minutes
UPDATE [Server].[Database].[dbo].[Item]  
SET     QtyOnHand = IH.QtyOnHand,
        QtyWorkInProgress = W.WIP   
FROM Avanti_InventoryHeader IH
INNER JOIN [Server].[Database].[dbo].[Item] I ON I.ItemNumber = IH.ItemNumber
LEFT JOIN @WIP W ON IH.ItemNumber = W.Item
WHERE isnumeric(left(IH.ItemNumber, 2)) = 0

Answer 1

我过去遇到过类似的问题，我不得不使用动态SQL来提高性能。

我发现当我使用远程表加入本地临时表时，SQL将所有数据带到本地服务器，然后过滤where语句中的内容。

在这种情况下，我会尝试在动态查询中使用SELECT UNION ALL将整个变量表@WIP作为嵌套表传递。

我说的是这样的事情：

 DECLARE @WIP Table(Item varchar(25), WIP int)

    --Get Work In Progress Numbers
    INSERT INTO @WIP
    select (UPC.ItemPrefix + '-' + UPC.ItemCode) As Item, SUM(PO.Quantity) As WIP
    --into #WIP
    from [NCLGS].[dbo].[AL_ItemUPCs] UPC
    INNER JOIN al_PO PO ON PO.UPCID = UPC.UPCID
    where PO.status in ('Assigned', 'New', 'UnAssigned', 'WaitingForFile')
    Group by  (UPC.ItemPrefix + '-' + UPC.ItemCode)

declare @SQL VARCHAR(MAX)

set @SQL = '
UPDATE [Server].[Database].[dbo].[Item]  
SET     QtyOnHand = IH.QtyOnHand,
        QtyWorkInProgress = W.WIP   
FROM Avanti_InventoryHeader IH
INNER JOIN [Server].[Database].[dbo].[Item] I 
    ON I.ItemNumber = IH.ItemNumber
LEFT JOIN ('

select @SQL = @SQL + 'select '''+w.Item+''' as Item, 
    '''+cast( w.WIP as varchar(50))+''' as WIP union all '
from @WIP W

set @SQL = @SQL + ' select NULL,0 ) W   
    ON IH.ItemNumber = W.Item
WHERE isnumeric(left(IH.ItemNumber, 2)) = 0 '

PRINT @SQL

它看起来不是很整洁，但它可能对你有效。

Answer 2

在尝试连接之前，我首先尝试将项目加载到本地表变量中。

DECLARE @WIP Table ( Item varchar(25), WIP int )
  --Get Work In Progress Numbers 
INSERT  INTO @WIP
        select  ( UPC.ItemPrefix + '-' + UPC.ItemCode ) As Item,
                SUM(PO.Quantity) As WIP 
        --into #WIP 
        from    [NCLGS].[dbo].[AL_ItemUPCs] UPC
                INNER JOIN al_PO PO ON PO.UPCID = UPC.UPCID
        where   PO.status in ( 'Assigned', 'New', 'UnAssigned',
                               'WaitingForFile' )
        Group by ( UPC.ItemPrefix + '-' + UPC.ItemCode )  

DECLARE @Item TABLE (ItemNumber  INT PRIMARY KEY, QtyOnHand INT)
SELECT ItemNumber, QtyOnHand
FROM   [Server].[Database].[dbo].[Item]    

--SLOW PART, takes over 17 minutes 
UPDATE  [Server].[Database].[dbo].[Item]
SET     QtyOnHand = IH.QtyOnHand,
        QtyWorkInProgress = W.WIP
FROM    Avanti_InventoryHeader IH
        INNER JOIN @item I ON I.ItemNumber = IH.ItemNumber
        LEFT JOIN @WIP W ON IH.ItemNumber = W.Item
WHERE   isnumeric(left(IH.ItemNumber, 2)) = 0

此外，您可以考虑通过从表变量中删除未更新的记录来进一步限制更新，并仅将更新的记录连接到链接服务器。

DECLARE @Item TABLE
    (
      ItemNumber INT PRIMARY KEY,
      QtyOnHand INT,
      updated BIT DEFAULT ( 0 ),
      WIP int
    )
SELECT  ItemNumber,
        QtyOnHand
FROM    [Server].[Database].[dbo].[Item] 

UPDATE  i
SET     i.QtyOnHand = ih.QtyOnHand,
        updated = 1
FROM    @item i
        INNER JOIN Avanti_InventoryHeader IH ON I.ItemNumber = IH.ItemNumber
        LEFT JOIN @WIP W ON IH.ItemNumber = W.Item
WHERE   isnumeric(left(IH.ItemNumber, 2)) = 0  

DELETE FROM @item WHERE updated = 0

UPDATE  I
SET     QtyOnHand = IH.QtyOnHand,
        QtyWorkInProgress = IH.WIP
FROM    [Server].[Database].[dbo].[Item] I
        INNER JOIN @item IH ON I.ItemNumber = IH.ItemNumber

Answer 3

尝试在此存储过程调用的远程服务器上创建存储过程。

在远程存储过程中，将您需要的数据提取到临时表中。然后在远程服务器上执行UPDATE / JOIN。

根据我的经验，尝试在链接服务器上进行连接可能会非常慢......在进行任何连接之前，通常可以更快地在一台服务器上获取所有必需的数据。

Answer 4

我找出了查询的真正问题，它正在更新数千条记录，即使这些记录没有改变。因此，我查询了已更改的记录，将其保存在表变量中，并仅更新已更改的记录。整个程序（不仅仅是这部分）从16分44秒到1分26秒。

--BEGIN EXPERIMENTAL ITEM UPDATE SECTION
    DECLARE @WIP Table(Item varchar(25), WIP int)

    --Get Work In Progress Numbers
    INSERT INTO @WIP
    select (UPC.ItemPrefix + '-' + UPC.ItemCode) As Item, SUM(PO.Quantity) As WIP
    --into #WIP
    from [NCLGS].[dbo].[AL_ItemUPCs] UPC
    INNER JOIN al_PO PO ON PO.UPCID = UPC.UPCID
    where PO.status in ('Assigned', 'New', 'UnAssigned', 'WaitingForFile')
    Group by  (UPC.ItemPrefix + '-' + UPC.ItemCode)

    Declare @Remote Table(Item varchar(25), QtyOnHand int, WIP int)

    INSERT INTO @REMOTE
    Select ItemNumber, QtyOnHand, QtyWorkInProgress
    from [BMPR.COM].[NCL-CustomerPortal].[dbo].[Item]

    DECLARE @ItemsToUpdate Table (Item varchar(50))

    INSERT INTO @ItemsToUpdate
    Select R.Item
    From @Remote R
    Inner join Avanti_InventoryHeader IH ON R.Item = IH.ItemNumber
    LEFT JOIN @WIP W ON R.Item = W.Item
    Where R.QtyOnHand <> IH.QtyOnHand 
    OR R.WIP <> W.WIP

    --Select * from @ItemsToUpdate

    UPDATE [BMPR.COM].[NCL-CustomerPortal].[dbo].[Item]  
    SET     QtyOnHand = IH.QtyOnHand,
            QtyWorkInProgress = W.WIP   
    FROM Avanti_InventoryHeader IH
    INNER JOIN [BMPR.COM].[NCL-CustomerPortal].[dbo].[Item] I ON I.ItemNumber = IH.ItemNumber
    LEFT JOIN @WIP W ON IH.ItemNumber = W.Item
    WHERE I.ItemNumber in ( Select * from @ItemsToUpdate )
--END EXPERIMENTAL ITEM UPDATE SECTION

对此方法有何评论？

Answer 5

PostgreSQL的UPDATE中只有一个ONLY子句，它只会更新上面提到的表。否则它会尝试更新您加入的所有表，这可能是瓶颈所在。你使用什么类型的SQL？如果是Postgres，可能还有其他一些，请尝试将更新行更改为

UPDATE ONLY [Server].[Database].[dbo].[Item]

我可以优化此SQL远程更新吗？

5 个答案: