聚合多个数组

Question

嘿，我无法正确进行聚合。

我有这个数据集，并且在集合中还有几百万个其他类似的文档：

{
  "_id": ObjectId("5757c73344ce54ae1d8b456c"),
  "hostname": "Baklap4",
  "timestamp": NumberLong(1465370500),
  "networkList": [
    {
      "name": "46.243.152.13",
      "openConnections": NumberLong(3)
    },
    {
      "name": "46.243.152.50",
      "openConnections": NumberLong(4)
    }
  ],
  "webserver": "nginx",
  "deviceList": [
    {
      "deviceName": "eth0",
      "receive": NumberLong(183263),
      "transmit": NumberLong(781595)
    },
    {
      "deviceName": "wlan0",
      "receive": NumberLong(0),
      "transmit": NumberLong(0)
    }
  ]
}

我想要什么：

我想获得一个结果集，我在 300 秒的时间跨度内对每个文档进行平均（每个数值）。

[
                [
                    '$match' => [
                        'timestamp' => ['$gte' => $todayMidnight],
                        'hostname' => $serverName
                    ]
                ],
                [
                    '$unwind' => '$networkList'
                ],
                [
                    '$unwind' => '$deviceList'
                ],
                [
                    '$group' => [
                        '_id' => [
                            'interval' => [
                                '$subtract' => [
                                    '$timestamp',
                                    [
                                        '$mod' => ['$timestamp', 300]
                                    ]
                                ]
                            ],
                            'network' => '$networkList.name',
                            'device' => '$deviceList.name',
                        ],
                        'openConnections' => [
                            '$sum' => '$networkList.openConnections'
                        ],
                        'cpuLoad' => [
                            '$avg' => '$cpuLoad'
                        ],
                        'bytesPerSecond' => [
                            '$avg' => '$bytesPerSecond'
                        ],
                        'requestsPerSecond' => [
                            '$avg' => '$requestsPerSecond'
                        ],
                        'webserver' => [
                            '$last' => '$webserver'
                        ],
                        'timestamp' => [
                            '$max' => '$timestamp'
                        ]
                    ]
                ],
                [
                    '$project' => [
                        '_id' => 0,
                        'timestamp' => 1,
                        'cpuLoad' => 1,
                        'bytesPerSecond' => 1,
                        'requestsPerSecond' => 1,
                        'webserver' => 1,
                        'openConnections' => 1,
                        'networkList' => '$networkList',
                        'deviceList' => '$_id.device',
                    ]
                ],
                [
                    '$sort' => [
                        'timestamp' => -1
                    ]
                ]
            ];

但这并没有给我一个包含所有设备和每个设备平均接收和传输字节数的列表。

如何获得这些？

Answer 1

根据给定的示例，我能够使用这个 mongo Shel 查询获得结果：

var projectTime = {
    $project : {
        _id : 1,
        hostname : 1,
        timestamp : 1,
        networkList : 1,
        webserver : 1,
        deviceList : 1,
        isoDate : {
            $add : [new Date(0), {
                    $multiply : ["$timestamp", 1000]
                }
            ]
        }
    }
}
var group = {
    $group : {

        "_id" : {
            time : {
                "$add" : [{
                        "$subtract" : [{
                                "$subtract" : ["$isoDate", new Date(0)]
                            }, {
                                "$mod" : [{
                                        "$subtract" : ["$isoDate", new Date(0)]
                                    },
                                    1000 * 60 * 5 // 1000 milsseconds * 60 seconds * 5 minutes
                                ]
                            }
                        ]
                    },
                    new Date(0)
                ]
            },
            "hostname" : "$hostname",
            "deviceList_deviceName" : "$deviceList.deviceName",
            "networkList_name" : "$networkList.name",
        },

        xreceive : {
            $sum : "$deviceList.receive"
        },
        xtransmit : {
            $sum : "$deviceList.transmit"
        },
        xopenConnections : {
            $avg : "$networkList.openConnections"
        },

    }
}

var unwindNetworkList = {
    $unwind : "$networkList"
}
var unwindSeviceList = {
    $unwind : "$deviceList"
}

var match = {
    $match : {
        "_id.time" : ISODate("2016-06-09T08:05:00.000Z")
    }
}

var finalProject = {
    $project : {
        _id : 0,
        timestamp : "$_id.time",
        hostname : "$_id.hostname",
        deviceList_deviceName : "$_id.deviceList_deviceName",
        networkList_name : "$_id.networkList_name",
        xreceive : 1,
        xtransmit : 1,
        xopenConnections : 1
    }
}
db.baklap.aggregate([projectTime, unwindNetworkList,
        unwindSeviceList,

        group,
        match,
        finalProject
    ])
db.baklap.findOne()

然后输出：

{
    "xreceive" : NumberLong(0),
    "xtransmit" : NumberLong(0),
    "xopenConnections" : 4.0,
    "timestamp" : ISODate("2016-06-09T08:05:00.000Z"),
    "hostname" : "Baklap4",
    "deviceList_deviceName" : "wlan0",
    "networkList_name" : "46.243.152.50"
}
{
    "xreceive" : NumberLong(183263),
    "xtransmit" : NumberLong(781595),
    "xopenConnections" : 4.0,
    "timestamp" : ISODate("2016-06-09T08:05:00.000Z"),
    "hostname" : "Baklap4",
    "deviceList_deviceName" : "eth0",
    "networkList_name" : "46.243.152.50"
}
{
    "xreceive" : NumberLong(183263),
    "xtransmit" : NumberLong(781595),
    "xopenConnections" : 3.0,
    "timestamp" : ISODate("2016-06-09T08:05:00.000Z"),
    "hostname" : "Baklap4",
    "deviceList_deviceName" : "eth0",
    "networkList_name" : "46.243.152.13"
}
{
    "xreceive" : NumberLong(0),
    "xtransmit" : NumberLong(0),
    "xopenConnections" : 3.0,
    "timestamp" : ISODate("2016-06-09T08:05:00.000Z"),
    "hostname" : "Baklap4",
    "deviceList_deviceName" : "wlan0",
    "networkList_name" : "46.243.152.13"
}

要注意的是，每次处理$unwind 时，我们的数据都会受到一点污染。这可能会在汇总数据时产生副作用（平均值将与 (2+2+3+3)/4 与 (2+3)/2) 相同）

要检查 - 您可以在小组阶段添加 x:{$push:"$$ROOT"} 并在管道执行后检查值 - 因为您将拥有给定数据周期的所有源文档