Question

我有两个收藏夹；一个是车辆（10 Kb）：

{
    "_id" : ObjectId("5d23c9fed6f3def48ad9e5e6"),
    "Accident_Index" : "201501BS70001",
    "accyr" : 2015,
    "Vehicle_Reference" : 1,
    "Vehicle_Type" : 19,
    "Towing_and_Articulation" : 0,
    "Vehicle_Manoeuvre" : 9,
    "Vehicle_Location-Restricted_Lane" : 0,
    "Junction_Location" : 8,
    "Skidding_and_Overturning" : 0,
    "Hit_Object_in_Carriageway" : 0,
    "Vehicle_Leaving_Carriageway" : 0,
    "Hit_Object_off_Carriageway" : 0,
    "1st_Point_of_Impact" : 1,
    "Was_Vehicle_Left_Hand_Drive" : 1,
    "Journey_Purpose_of_Driver" : 1,
    "Sex_of_Driver" : 1,
    "Age_Band_of_Driver" : -1,
    "Engine_Capacity_(CC)" : 2143,
    "Propulsion_Code" : 2,
    "Age_of_Vehicle" : 4,
    "Driver_IMD_Decile" : -1,
    "Driver_Home_Area_Type" : -1,
    "make" : "MERCEDES-BENZ",
    "model" : "SPRINTER 310 CDI"
}

另一个是事故（250mb）：

{
    "_id" : ObjectId("5d23c9f3d6f3def48ad7c23c"),
    "Accident_Index" : "201501BS70001",
    "Location_Easting_OSGR" : 524420,
    "Location_Northing_OSGR" : 181080,
    "Longitude" : -0.208327,
    "Latitude" : 51.514952,
    "Police_Force" : 1,
    "Accident_Severity" : 3,
    "Number_of_Vehicles" : 1,
    "Number_of_Casualties" : 1,
    "Date" : "13/01/2015",
    "Day_of_Week" : 3,
    "Time" : "07:40",
    "Local_Authority_(District)" : 12,
    "Local_Authority_(Highway)" : "E09000020",
    "1st_Road_Class" : 4,
    "1st_Road_Number" : 450,
    "Road_Type" : 6,
    "Speed_limit" : 30,
    "Junction_Detail" : 6,
    "Junction_Control" : 4,
    "2nd_Road_Class" : 6,
    "2nd_Road_Number" : 0,
    "Pedestrian_Crossing-Human_Control" : 0,
    "Pedestrian_Crossing-Physical_Facilities" : 0,
    "Light_Conditions" : 1,
    "Weather_Conditions" : 1,
    "Road_Surface_Conditions" : 2,
    "Special_Conditions_at_Site" : 0,
    "Carriageway_Hazards" : 0,
    "Urban_or_Rural_Area" : 1,
    "Did_Police_Officer_Attend_Scene_of_Accident" : 2,
    "LSOA_of_Accident_Location" : "E01002874"
}

现在，我正在尝试对事故收集运行汇总功能，并创建一个名为 combined 的新收集，但是合并需要花费很多时间。这是我的聚合函数：

db.accidents.aggregate([ 
   {$lookup:{ 
           from:"vehicles", 
           localField: "Accident_Index", 
           foreignField: "Accident_Index", 
           as: "Vehicles"}
           }, 
   {$unwind: "$Vehicles"}, 
   {$project: {
              Accident_Index:1,  
              Accident_Severity:1, 
              _id:0, 
              Vehicle_Type: "$vehicles.Vehicle_Type"}
              }, 
   {$out:"combined"}
])

你知道怎么了吗？

MongoDB聚合时间过长

0 个答案: