SELECT语句需要几小时才能执行

Question

我试图运行这个SELECT语句，但我需要数小时才能执行。我也在这些表上创建了索引。

SELECT DISTINCT 
    j.Name AS State, 
    l.DisplayName AS ServiceCenter, 
    l.JurisdictionID, 
    e.LocationID, 
    ConvictionStateID AS RegionId, 
    FeeGroupID, 
    e.VehicleID , 
    ServiceDate, 
    evd.EventlogID, 
    v.ClientID, 
    e.EventLogServiceID, 
    evd.EventlogDetailID, 
    EvtDT AS EventDate, 
    EvtVal AS EventValue, 
    evd.EventLogCodeID, 
    UPPER(SerialNumber) AS SerialNumber, 
    UPPER(RelayNum) AS RelayNumber, 
    edp.FileName, 
    GPSLatitude 
FROM 
    [MM\PLUSREPORT5].lsa_plus_jur_nico.dbo.EventLogDetail evd 
INNER JOIN 
    [MM\PLUSREPORT5].lsa_plus_jur_nico.dbo.EventLog e ON evd.EventlogID = e.EventlogID 
INNER JOIN 
    [MM\PLUSREPORT5].lsa_plus_jur_nico.dbo.Vehicle v ON e.VehicleID = v.VehicleID 
INNER JOIN 
    [MM\PLUSREPORT5].lsa_plus_jur_nico.dbo.Client c ON v.ClientID = c.ClientID 
INNER JOIN 
    [MM\PLUSREPORT5].lsa_plus_base.dbo.Location l ON e.LocationID = l.LocationID 
INNER JOIN 
    [MM\PLUSREPORT5].lsa_plus_base.dbo.Jurisdiction j ON l.JurisdictionID = j.JurisdictionID 
LEFT JOIN 
    [MM\PLUSREPORT5].lsa_plus_jur_nico.dbo.EventLogDetailPhoto edp ON evd.EventLogDetailId = edp.EventLogDetailId 

Excution plan，也嵌入在下面。

Answer 1

你没有得到任何并行和排序被弹起。

检查您的索引是否配置为DESC顺序。

向后扫描索引的限制是它们不能并行。

如果可能，也尝试并删除DISTINCT，这可以添加相同的限制。