Question

我正在使用更新连接查询来更新一些记录。我实际上是将索引表连接到自身，并更新满足模式的位置。

此查询适用于大约一百万条记录，但有1400万条记录，它只是没有扩展。我这样做的原因是因为我所知道的唯一其他选择是使用光标，这本来是非常残酷的。

现在查询运行时间超过12小时。任何帮助找到更好的方法来做到这一点将非常感激。我正在使用SQL Server Management Studio。对于下面的查询，以下是在AIS_Positions表中创建索引的方式：

CREATE INDEX SID ON AIS_Positions (Id)

UPDATE R1 
SET
    BOUNDARY = 'BERTH',
    TRAVEL_MODE = 'HOTEL',
    BerthStartFlag = 'YES',
    BerthStartTime = R1.IntervalStart,
    BerthEndTime = R2.IntervalEnd,
    BerthStart_ID = R1.Id,
    BerthEnd_ID = R2.Id
FROM 
    AIS_Positions R1
INNER JOIN 
    AIS_Positions R2 ON R1.MMSI = R2.MMSI
                     AND R1.ID < R2.ID
                     AND R1.IntervalSpeed <= 0.1
                     AND R2.IntervalSpeed <= 0.1
                     AND DATEDIFF(HOUR, R1.POSITIONTIME, R2.POSITIONTIME) BETWEEN 1 AND 72
                     AND (SELECT TOP 1 IntervalSpeed 
                          FROM AIS_Positions 
                          WHERE MMSI = R1.MMSI AND ID = R1.ID-1) > 0.1
                     AND (SELECT TOP 1 IntervalSpeed 
                          FROM AIS_Positions 
                          WHERE MMSI = R1.MMSI AND ID = R2.ID+1) > 0.1
                     AND (SELECT TOP 1 Boundary 
                          FROM AIS_Positions 
                          WHERE MMSI = R1.MMSI AND ID = R1.ID-1) IS NULL

Answer 1

这可能是一个好的开始：

/*
 create nonclustered index [ix_ais_positions_mmsi_inc] on ais_positions 
   (mmsi) 
   include (id, intervalspeed, boundary, PositionTime, IntervalStart, IntervalEnd);
*/


update R1 set
    boundary = 'berth',
    travel_mode = 'hotel',
    BerthStartFlag = 'yes',
    BerthStartTime = R1.IntervalStart,
    BerthEndTime = R2.IntervalEnd,
    BerthStart_id = R1.Id,
    BerthEnd_id = R2.Id
from ais_positions R1

inner join ais_positions R2

    on R1.mmsi = R2.mmsi

    and R1.id < R2.id
    --How many matches does R1.id < R2.id yield? Is this updating the same row more than once?

    and R1.IntervalSpeed <= 0.1

    and R2.IntervalSpeed <= 0.1
    --and datediff(hour, R1.positiontime, R2.positiontime) between 1 and 72
    and datediff(hour, R1.positiontime, R2.positiontime) >= 1 and datediff(hour, R1.positiontime, R2.positiontime) <= 72

    --and (select top 1 IntervalSpeed from ais_positions where mmsi = R1.mmsi and id = R1.id-1) > 0.1
    and exists (select 1 from ais_positions i where i.mmsi = R1.mmsi and i.id = R1.id-1 and i.IntervalSpeed > 0.1 and i.Boundary is null)

    --and (select top 1 IntervalSpeed from ais_positions where mmsi = R1.mmsi and id = R2.id+1) > 0.1
    and exists (select 1 from ais_positions where mmsi = R1.mmsi and id = R2.id+1 and IntervalSpeed > 0.1)
    --and (select top 1 Boundary from ais_positions where mmsi = R1.mmsi and id=R1.id-1) is null

Answer 2

您是否考虑过使用临时表来查询子查询的条件？您的查询可能正在为它们上面的查询的每一行运行子查询。也许是这样的：

SELECT A1.ID, A1.IntervalSpeed as topint1
INTO #Int_tabl_1
FROM AIS_Positions as A1
INNER JOIN AIS_Positions as A2
ON A1.MMSI = A2.MMSI AND A1.ID = A2.ID -1

SELECT A1.ID, A1.IntervalSpeed as topint2
INTO #Int_tabl_2
FROM AIS_Positions as A1
INNER JOIN AIS_Positions as A2
ON A1.MMSI = A2.MMSI AND A1.ID = A2.ID+1

SELECT A1.ID, A1.Boundary
INTO #Bound_tbl
FROM AIS_Positions as A1
INNER JOIN AIS_Positions as A2
ON A1.MMSI = A2.MMSI AND A1.ID = A2.ID-1

然后测试

topint1 > 0.1，topint2 > 0.1和Boundary is null

如何在SQL Server 2014中优化此更新连接查询？

2 个答案: