如何提高SQL MERGE语句的性能

Question

我有一份工作，我正在运行以同步不同内部服务器上的两个数据库之间的数据。一台服务器是FrontRange HEAT产品的后端数据库。第二个是我们自己的报告数据库，我们用它来撰写报告和其他内部用途。

我们在工作中的第一种方法是这样的： 查询我们需要的HEAT数据库表中的所有数据并填充本地临时表。然后将这些数据复制到适当的表格中。这可以工作，但他们每次都使用TRUNCATE表并重新填充而无需为索引或碎片做任何事情。所以我认为这可能是使用SQL合并语句的一个很好的选择。

所以我们的第二种方法为每个表使用合并语句。它极大地提高了流程的速度，但它似乎锁定了源表，以便用户在尝试保存信息时注意到15-30秒的延迟。要使合并仅处理已更改或新建的记录，我在select上添加了BINARY_CHECKSUM函数并将其存储在我的一侧，以便我可以避免更新未更改的记录。似乎很昂贵，但为每个记录调用它。这张表有大约30万条记录。

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

这里是我的米格声明我使用了CallLog表：

-- 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

既然你在SQL 2008，怎么样Change Data Capture？您可以在一段时间内获得净更改并仅处理该更改（与推动每次更改的复制相反，即使更新相同数据10次也是如此）。

Answer 2

我想你可以通过确定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，其中包含应该受到影响的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，您可以在您的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 
    );