在鏈接服務器表上加入時提高查詢性能

Question

不幸的是，作為我們修復數據中心的臨時措施，我需要運行以下跨服務器查詢，任何人都可以建議我如何提高性能...

因為必須在游標開頭運行此語句

SELECT t.SearchId, t.VisitSourceId, t.SiteDomainId, t.trpUTMid, t.FlightPlus, t.StartDate,
t.CountryId, t.ProvinceId, t.Locationid, t.PlaceId, t.EstabId, t.CheckInDate, 
t.CheckOutDate, t.Rooms, t.Room1Adults, t.Room1Children, t.Room2Adults, t.Room2Children, 
t.Room3Adults, t.Room3Children, tc.OutcomeDate, tc.OutcomeId, tc.HotelsFound, tc.Notes

FROM [MLT_VisitTracking].[dbo].TrackingAcomSearches_tbl t
INNER JOIN TrackingAcomSearchesOutcome_tbl tc
ON t.trpUTMid = tc.trpUTMid
LEFT JOIN [YAZOO].[MLT_VisitTracking].[dbo].TrackingAcomSearches_tbl tid
ON t.trpUTMid = tid.trpUTMid
WHERE tid.trpUTMid IS NULL

Answer 1

一種可能的選擇是將遠程表復制到本地服務器。 這會將所有表放在同一台服務器上，使優化器能夠使用統計信息生成最佳計划。 由於您只使用trpUTMid，因此您可以復制該列。

另一種選擇是使用臨時表。 同樣的想法，在同一台服務器上獲取所有表：

SELECT trpUTMid
INTO #Yazoo_TrackingAcomSearches_tbl
FROM [YAZOO].[MLT_VisitTracking].[dbo].TrackingAcomSearches_tbl


SELECT t.SearchId, t.VisitSourceId, t.SiteDomainId, t.trpUTMid, t.FlightPlus, t.StartDate,
t.CountryId, t.ProvinceId, t.Locationid, t.PlaceId, t.EstabId, t.CheckInDate, 
t.CheckOutDate, t.Rooms, t.Room1Adults, t.Room1Children, t.Room2Adults, t.Room2Children, 
t.Room3Adults, t.Room3Children, tc.OutcomeDate, tc.OutcomeId, tc.HotelsFound, tc.Notes

FROM [MLT_VisitTracking].[dbo].TrackingAcomSearches_tbl t
INNER JOIN TrackingAcomSearchesOutcome_tbl tc
ON t.trpUTMid = tc.trpUTMid
LEFT JOIN #Yazoo_TrackingAcomSearches_tbl tid
ON t.trpUTMid = tid.trpUTMid
WHERE tid.trpUTMid IS NULL

您還可以在臨時表上創建索引以提高性能。

我還建議檢查是否存在缺乏而不是舊的左連接為null（閱讀此內容以獲取更多信息）：

SELECT trpUTMid
INTO #Yazoo_TrackingAcomSearches_tbl
FROM [YAZOO].[MLT_VisitTracking].[dbo].TrackingAcomSearches_tbl


SELECT t.SearchId, t.VisitSourceId, t.SiteDomainId, t.trpUTMid, t.FlightPlus, t.StartDate,
t.CountryId, t.ProvinceId, t.Locationid, t.PlaceId, t.EstabId, t.CheckInDate, 
t.CheckOutDate, t.Rooms, t.Room1Adults, t.Room1Children, t.Room2Adults, t.Room2Children, 
t.Room3Adults, t.Room3Children, tc.OutcomeDate, tc.OutcomeId, tc.HotelsFound, tc.Notes

FROM [MLT_VisitTracking].[dbo].TrackingAcomSearches_tbl t
INNER JOIN TrackingAcomSearchesOutcome_tbl tc
ON t.trpUTMid = tc.trpUTMid
WHERE NOT EXISTS (
    SELECT NULL 
    FROM #Yazoo_TrackingAcomSearches_tbl
    WHERE trpUTMid = t.trpUTMid
)

Answer 2

請嘗試以下查詢

;with cte
    as(
    SELECT tc.OutcomeDate, tc.OutcomeId, tc.HotelsFound, tc.Notes
    GROUP BY [BatchId]  FROM TrackingAcomSearchesOutcome_tbl tc
    )
     SELECT t.SearchId, t.VisitSourceId, t.SiteDomainId, t.trpUTMid, t.FlightPlus, t.StartDate,
    t.CountryId, t.ProvinceId, t.Locationid, t.PlaceId, t.EstabId, t.CheckInDate, 
    t.CheckOutDate, t.Rooms, t.Room1Adults, t.Room1Children, t.Room2Adults, t.Room2Children, 
    t.Room3Adults, t.Room3Children

    FROM [MLT_VisitTracking].[dbo].TrackingAcomSearches_tbl t
    INNER JOIN cte as tbl ON t.trpUTMid = tbl .trpUTMid
    LEFT JOIN [YAZOO].[MLT_VisitTracking].[dbo].TrackingAcomSearches_tbl tid
    ON t.trpUTMid = tbl .trpUTMid
    WHERE tid.trpUTMid IS NULL