Exceeded memory limit for $group, but didn't allow external sort

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Exceeded memory limit for $group, but didn’t allow external sort

因为Mongodb的聚合操作管道的输出结果不能超过16M，超过16M会出现错误。

• Mongodb

allowDiskUse: true

db.stocks.aggregate(
    [
        { $project : { cusip: 1, date: 1, price: 1, _id: 0 } },
        { $sort : { cusip : 1, date: 1 } }
    ],
    {
        allowDiskUse: true
    }
);

• Mongoose

allowDiskUse(true)

await stocks.aggregate([{ $match:{price:1}}, {$group: {_id:{date:"$date"}, sum:{$sum:"$price"}}}]).allowDiskUse(true);