与组的MongoDB聚合查询太慢

Question

我下面有Signal记录集合：

Signal records:

[
  {
    "id": "5dc250e0d972e71c3b3e6e88",
    "signalStrength": -180,
    "signalbars": "3",
    "employee": "5db59227f0204855654075ee",
    "store": "5dc25092d972e71c3b3e6e87",
    "carrierName": "LT&T"
  },
  {
    "id": "5dc251f723760a24de167f8e",
    "signalStrength": -180,
    "signalbars": "3",
    "employee": "5db59227f0204855654075ee",
    "store": "5dc25092d972e71c3b3e6e87",
    "carrierName": "Sprint"
  },
  {
    "id": "5dc289affd1ea02f0fceb9ac",
    "signalStrength": -80,
    "signalbars": "3",
    "employee": "5db59227f0204855654075ee",
    "store": "5dc2899bfd1ea02f0fceb9ab",
    "carrierName": "LT&T"
  }
]

基本上，我需要根据运营商名称的平均值和拥有该运营商名称的信号记录的员工总数来计算

我需要得到以下结果

[
      {
        "_id": "LT&T",
        "averageSignal": -130,
        "strongestSignal": -80,
        "weakestSignal": -180,
        "averageBars": 3,
        "totalTests": 2,
        "totalTesters": 1
      },
      {
        "_id": "Sprint",
        "averageSignal": -180,
        "strongestSignal": -180,
        "weakestSignal": -180,
        "averageBars": 3,
        "totalTests": 1,
        "totalTesters": 1
      }
]

我的代码在下面进行汇总：

[
  {
    $match: query
  },
  {
    $group:
    {
      _id: "$carrierName",
      employee: { "$addToSet": "$employee" },
      averageSignal: { $avg: "$signalStrength" },
      strongestSignal: { $max: "$signalStrength" },
      weakestSignal: { $min: "$signalStrength" },
      averageBars: { $avg: "$signalbars" },
      totalTests: { $sum: 1 },
      totalTesters: { $sum: 1 },
    }
  },
  { $addFields: { totalTesters: { $size: "$employee" } } },
  { $sort: { averageSignal: -1 } },
];

它按我的预期工作。但是，尽管记录在5万以内，但要花很长时间才能得到结果。

有人可以帮助我提高性能吗？