Mongo错误查询ExceededMemoryLimitNoDiskUseAllowed

Question

当我使用此查询时出现此错误：

db2.collection('candata')
.aggregate([{$sort:{time:-1}},{$group:{_id:{batteryId:"$batteryId"},soctime:{$first:"$time"},GPSStatus:{$first:"$GPSStatus"},CANStatus:{$first:"$CANStatus"},soc: { $first : "$socpercentage" },charging_status: { $first : "$charging_status" },status: { $first : "$status" }}},{$sort:{'_id.batteryId':1}},{$lookup:{from : "swap_table",localField : "_id.batteryId",foreignField:"batteryId",as:"swap"}},{$lookup:{from : "battery_status_table",localField : "_id.batteryId",foreignField:"batteryId",as:"battery_statustb"}}])

我需要做什么改变？我不想改变查询，那么如何增加这个限制，或者我需要走一些数据归档方法？

Answer 1

allowDiskUse在查询末尾添加并将其设置为 true，使其变为如下所示：

 db2.collection('candata')
.aggregate([{$sort:{time:-1}},{$group:{_id:{batteryId:"$batteryId"},soctime:{$first:"$time"},GPSStatus:{$first:"$GPSStatus"},CANStatus:{$first:"$CANStatus"},soc: { $first : "$socpercentage" },charging_status: { $first : "$charging_status" },status: { $first : "$status" }}},{$sort:{'_id.batteryId':1}},{$lookup:{from : "swap_table",localField : "_id.batteryId",foreignField:"batteryId",as:"swap"}},{$lookup:{from : "battery_status_table",localField : "_id.batteryId",foreignField:"batteryId",as:"battery_statustb"}}]).allowDiskUse(true)

Answer 2

您可以添加allowDiskUse与第二个聚合函数，例如：

db.getCollection("loans_unique").aggregate([{
    "$group": {
        "_id": {
            phone: "$phone",
            address: "$address",
            title: "$title"
        },
        "count": {
            "$sum": 1
        }
       }
},
    {
        $sort: {
            "count": -1
        }
    },
    {
        $match: {
            "count": {$gt: 1}
        }
    }
], {
    allowDiskUse: true
})