如何提高SQL MERGE语句的性能

Question

我当前正在运行一项工作，以在不同内部服务器上的两个数据库之间同步数据。一台服务器是 FrontRange 的 HEAT 产品的后端数据库。第二个是我们自己的报告数据库，我们用于报告编写和其他内部用途。

我们的第一个工作方法是这样的： 从我们想要的 HEAT 数据库表中查询所有数据并填充本地临时表。然后将该数据复制到适当的表中。这可行，但他们每次都会截断表并重新填充，而不对索引或碎片执行任何操作。所以我认为这可能是使用 SQL 合并语句的一个很好的选择。

因此，我们的第二种方法对每个表使用合并语句。它极大地提高了处理速度，但似乎锁定了源表，因此用户在尝试保存信息时会注意到 15-30 秒的延迟。为了使合并仅处理已更改或新的记录，我在选择上添加了 BINARY_CHECKSUM 函数并将其存储在我这边，这样我就可以避免更新未更改的记录。不过，为每条记录调用它似乎很昂贵。该表大约有 300k 条记录。

我想知道是否有更好的方法来尝试同步我忽略的这两个表。我唯一的限制是我真的不想更改源表上的任何内容，因为它是第三方应用程序。

这是我用于 CallLog 表的 mege 语句：

-- Merge CallLog
MERGE INTO [CallLog] AS T
USING (
        SELECT
            [CallID], [CustID], [CustType], [CallType], [Tracker], [CallStatus], [Priority], [CDuration], [CallCount], [StopWatch], [ClosedBy],
            [ClosedDate], [ClosedTime], [Cause], [CallDesc], [CloseDesc], [RecvdBy], [RecvdDate], [RecvdTime], [ModBy], [ModDate], [ModTime],
            [DTLastMod], [CallSource], [PriorityName], [QuickCall], [Category], [TotalAsgnmntTime], [CatHeading], [TotalJournalTime],
            [TotalTime], [SL_Warn_Goal], [SL_Warn_Date], [SL_Warn_Time], [SL_Complete_Goal], [SL_Complete_Date], [SL_Complete_Time],
            [SL_Clock_Status], [SL_Button_Status], [FirstResolution], [SL_Complete_Status], [SubCallType], [ImpactValue], [ImpactName],
            [UrgencyValue], [UrgencyName], [LinkedToProblem], [LinkedToProblemCustID], [LinkedToProblemName], [LinkedToProblemBy],
            [LinkedToProblemDate], [LinkedToProblemTime], [SLAStatus], [issue_text], [issue_number], [ResCheck], [AsgnAckBy], [AsgnAckDate],
            [AsgnAckTime], [Resolvedby], [ResolvedDate], [ResolvedTime], [ACheck], [ACKEmail], [LinkedToChange], [LinkedToChangeCustID],
            [LinkedToChangeName], [LinkedToChangeBy], [LInkedToChangeDate], [LinkedToChangeTime], [IssueTypeProblem], [IssueTypeChange],
            [RespWarningD], [RespWarningT], [RespMissedD], [RespMissedT], [ResoWarningD], [ResoWarningT], [ResoMissedD], [ResoMissedT],
            [IssueType], [SubCategory], [Diagnosis], [HSSAlert], [ErrorMessage], [ProblemType], [diagnosising], [KB], [CloseStatus],
            [SuggestedAssignGrp], [DefaultGrp], [DefaultGrpTF], [OtherAssign], [WorkAround], [ChangeReason], [CloseProblem], [AssgnApp],
            [AssgnAppRes], [DenyChk], [ImplementationApp], [ImplementationAppRes], [WorkAroundChk], [NoDenyChk], [ImpNoDenyChk],
            [ImpDenyChk], [ChangeStatus], [ReadyToClose], [ResolveOrReAssign], [TicketLabel], [CatCallType], [IssueType_PK], [Category_PK],
            [SubCategory_PK], [CallType_PK], [SubCallType_PK], BINARY_CHECKSUM(*) AS [Checksum]
        FROM
            [CHLA-HEATDB].SDIT.dbo.calllog
    ) AS S
ON (T.[CallID] = S.[CallID])
WHEN MATCHED AND T.[Checksum] <> S.[Checksum] THEN 
    UPDATE SET
        T.[CallID] = S.[CallID], T.[CustID] = S.[CustID], T.[CustType] = S.[CustType], T.[CallType] = S.[CallType],
        T.[Tracker] = S.[Tracker], t.[CallStatus] = S.[CallStatus], T.[Priority] = S.[Priority], T.[CDuration] = S.[CDuration],
        T.[CallCount] = S.[CallCount], T.[StopWatch] = S.[StopWatch], T.[ClosedBy] = S.[ClosedBy],
        T.[ClosedDate] = S.[ClosedDate], T.[ClosedTime] = S.[ClosedTime], T.[Cause] = S.[Cause], T.[CallDesc] = S.[CallDesc],
        T.[CloseDesc] = S.[CloseDesc], T.[RecvdBy] = S.[RecvdBy], T.[RecvdDate] = S.[RecvdDate], T.[RecvdTime] = S.[RecvdTime],
        T.[ModBy] = S.[ModBy], T.[ModDate] = S.[ModDate], T.[ModTime] = S.[ModTime], T.[DTLastMod] = S.[DTLastMod],
        T.[CallSource] = S.[CallSource], T.[PriorityName] = S.[PriorityName], T.[QuickCall] = S.[QuickCall],
        T.[Category] = S.[Category], T.[TotalAsgnmntTime] = S.[TotalAsgnmntTime], T.[CatHeading] = S.[CatHeading],
        T.[TotalJournalTime] = S.[TotalJournalTime], T.[TotalTime] = S.[TotalTime], T.[SL_Warn_Goal] = S.[SL_Warn_Goal],
        T.[SL_Warn_Date] = S.[SL_Warn_Date], T.[SL_Warn_Time] = S.[SL_Warn_Time], T.[SL_Complete_Goal] = S.[SL_Complete_Goal],
        T.[SL_Complete_Date] = S.[SL_Complete_Date], T.[SL_Complete_Time] = S.[SL_Complete_Time],
        T.[SL_Clock_Status] = S.[SL_Clock_Status], T.[SL_Button_Status] = S.[SL_Button_Status],
        T.[FirstResolution] = S.[FirstResolution], T.[SL_Complete_Status] = S.[SL_Complete_Status],
        T.[SubCallType] = S.[SubCallType], T.[ImpactValue] = S.[ImpactValue], T.[ImpactName] = S.[ImpactName],
        T.[UrgencyValue] = S.[UrgencyValue], T.[UrgencyName] = S.[UrgencyName], T.[LinkedToProblem] = S.[LinkedToProblem],
        T.[LinkedToProblemCustID] = S.[LinkedToProblemCustID], T.[LinkedToProblemName] = S.[LinkedToProblemName],
        T.[LinkedToProblemBy] = S.[LinkedToProblemBy], T.[LinkedToProblemDate] = S.[LinkedToProblemDate],
        T.[LinkedToProblemTime] = S.[LinkedToProblemTime], T.[SLAStatus] = S.[SLAStatus], T.[issue_text] = S.[issue_text],
        T.[issue_number] = S.[issue_number], T.[ResCheck] = S.[ResCheck], T.[AsgnAckBy] = S.[AsgnAckBy],
        T.[AsgnAckDate] = S.[AsgnAckDate], T.[AsgnAckTime] = S.[AsgnAckTime], T.[Resolvedby] = S.[Resolvedby],
        T.[ResolvedDate] = S.[ResolvedDate], T.[ResolvedTime] = S.[ResolvedTime], T.[ACheck] = S.[ACheck],
        T.[ACKEmail] = S.[ACKEmail], T.[LinkedToChange] = S.[LinkedToChange], T.[LinkedToChangeCustID] = S.[LinkedToChangeCustID],
        T.[LinkedToChangeName] = S.[LinkedToChangeName], T.[LinkedToChangeBy] = S.[LinkedToChangeBy],
        T.[LInkedToChangeDate] = S.[LInkedToChangeDate], T.[LinkedToChangeTime] = S.[LinkedToChangeTime],
        T.[IssueTypeProblem] = S.[IssueTypeProblem], T.[IssueTypeChange] = S.[IssueTypeChange],
        T.[RespWarningD] = S.[RespWarningD], T.[RespWarningT] = S.[RespWarningT], T.[RespMissedD] = S.[RespMissedD],
        T.[RespMissedT] = S.[RespMissedT], T.[ResoWarningD] = S.[ResoWarningD], T.[ResoWarningT] = S.[ResoWarningT],
        T.[ResoMissedD] = S.[ResoMissedD], T.[ResoMissedT] = S.[ResoMissedT], T.[IssueType] = S.[IssueType],
        T.[SubCategory] = S.[SubCategory], T.[Diagnosis] = S.[Diagnosis], T.[HSSAlert] = S.[HSSAlert],
        T.[ErrorMessage] = S.[ErrorMessage], T.[ProblemType] = S.[ProblemType], T.[diagnosising] = S.[diagnosising],
        T.[KB] = S.[KB], T.[CloseStatus] = S.[CloseStatus], T.[SuggestedAssignGrp] = S.[SuggestedAssignGrp],
        T.[DefaultGrp] = S.[DefaultGrp], T.[DefaultGrpTF] = S.[DefaultGrpTF], T.[OtherAssign] = S.[OtherAssign],
        T.[WorkAround] = S.[WorkAround], T.[ChangeReason] = S.[ChangeReason], T.[CloseProblem] = S.[CloseProblem],
        T.[AssgnApp] = S.[AssgnApp], T.[AssgnAppRes] = S.[AssgnAppRes], T.[DenyChk] = S.[DenyChk],
        T.[ImplementationApp] = S.[ImplementationApp], T.[ImplementationAppRes] = S.[ImplementationAppRes],
        T.[WorkAroundChk] = S.[WorkAroundChk], T.[NoDenyChk] = S.[NoDenyChk], T.[ImpNoDenyChk] = S.[ImpNoDenyChk],
        T.[ImpDenyChk] = S.[ImpDenyChk], T.[ChangeStatus] = S.[ChangeStatus], T.[ReadyToClose] = S.[ReadyToClose],
        T.[ResolveOrReAssign] = S.[ResolveOrReAssign], T.[TicketLabel] = S.[TicketLabel], T.[CatCallType] = S.[CatCallType],
        T.[IssueType_PK] = S.[IssueType_PK], T.[Category_PK] = S.[Category_PK], T.[SubCategory_PK] = S.[SubCategory_PK],
        T.[CallType_PK] = S.[CallType_PK], T.[SubCallType_PK] = S.[SubCallType_PK], T.[Checksum] = S.[Checksum]
WHEN NOT MATCHED 
    THEN INSERT VALUES
    (
        S.[CallID], S.[CustID], S.[CustType], S.[CallType], S.[Tracker], S.[CallStatus], S.[Priority], S.[CDuration],
        S.[CallCount], S.[StopWatch], S.[ClosedBy], S.[ClosedDate], S.[ClosedTime], S.[Cause], S.[CallDesc], S.[CloseDesc],
        S.[RecvdBy], S.[RecvdDate], S.[RecvdTime], S.[ModBy], S.[ModDate], S.[ModTime], S.[DTLastMod], S.[CallSource],
        S.[PriorityName], S.[QuickCall], S.[Category], S.[TotalAsgnmntTime], S.[CatHeading], S.[TotalJournalTime], S.[TotalTime],
        S.[SL_Warn_Goal], S.[SL_Warn_Date], S.[SL_Warn_Time], S.[SL_Complete_Goal], S.[SL_Complete_Date], S.[SL_Complete_Time],
        S.[SL_Clock_Status], S.[SL_Button_Status], S.[FirstResolution], S.[SL_Complete_Status], S.[SubCallType], S.[ImpactValue],
        S.[ImpactName], S.[UrgencyValue], S.[UrgencyName], S.[LinkedToProblem], S.[LinkedToProblemCustID], S.[LinkedToProblemName],
        S.[LinkedToProblemBy], S.[LinkedToProblemDate], S.[LinkedToProblemTime], S.[SLAStatus], S.[issue_text], S.[issue_number],
        S.[ResCheck], S.[AsgnAckBy], S.[AsgnAckDate], S.[AsgnAckTime], S.[Resolvedby], S.[ResolvedDate], S.[ResolvedTime], S.[ACheck],
        S.[ACKEmail], S.[LinkedToChange], S.[LinkedToChangeCustID], S.[LinkedToChangeName], S.[LinkedToChangeBy],
        S.[LInkedToChangeDate], S.[LinkedToChangeTime], S.[IssueTypeProblem], S.[IssueTypeChange], S.[RespWarningD],
        S.[RespWarningT], S.[RespMissedD], S.[RespMissedT], S.[ResoWarningD], S.[ResoWarningT], S.[ResoMissedD], S.[ResoMissedT],
        S.[IssueType], S.[SubCategory], S.[Diagnosis], S.[HSSAlert], S.[ErrorMessage], S.[ProblemType], S.[diagnosising], S.[KB],
        S.[CloseStatus], S.[SuggestedAssignGrp], S.[DefaultGrp], S.[DefaultGrpTF], S.[OtherAssign], S.[WorkAround], S.[ChangeReason],
        S.[CloseProblem], S.[AssgnApp], S.[AssgnAppRes], S.[DenyChk], S.[ImplementationApp], S.[ImplementationAppRes],
        S.[WorkAroundChk], S.[NoDenyChk], S.[ImpNoDenyChk], S.[ImpDenyChk], S.[ChangeStatus], S.[ReadyToClose],
        S.[ResolveOrReAssign], S.[TicketLabel], S.[CatCallType], S.[IssueType_PK], S.[Category_PK], S.[SubCategory_PK],
        S.[CallType_PK], S.[SubCallType_PK], S.[Checksum]
    );
GO

Answer 1

由于您使用的是 SQL 2008，更改如何数据捕获？您可以获得一段时间内的净更改并仅对其进行处理（与推送每个更改的复制相反，即使您更新相同的数据 10 次）。

Answer 2

我认为您可以通过弄清楚在合并语句之前修改/插入哪些行来提高性能。

您可以创建一个临时表，其中包含应受影响的 CallID。
也许是这样的。

;with cteSource as
(
  select
    S.CallID,
    binary_checksum(*) as [CheckSum]
  from [CHLA-HEATDB].SDIT.dbo.calllog
)  
select
  S.CallID,
  S.[CheckSum]
into #TmpSource
from cteSource as S    
  left outer join CallLog as T
    on S.CallID = T.CallID and
       S.[CheckSum] = T.[CheckSum]
where T.CallID is null

然后您可以在 using select 语句中使用该表。

MERGE INTO [CallLog] AS T
USING (
        SELECT
            [CallID], 

            -- A lot of fields

            T.[CheckSum] AS [Checksum]
        FROM
            [CHLA-HEATDB].SDIT.dbo.calllog as C
              inner join #TmpSource as Tmp
                on C.CallID = Tmp.CallID
    ) AS S
ON (T.[CallID] = S.[CallID])
WHEN MATCHED THEN -- Probably don't need this AND T.[Checksum] <> S.[Checksum] THEN 
    UPDATE SET
        T.[CallID] = S.[CallID],
        -- More fields here
WHEN NOT MATCHED 
    THEN INSERT VALUES
    (
        S.[CallID], 
        -- More fields here
    );