allow nested $facet in another $facet of aggregate

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    • Type: Improvement
    • Resolution: Unresolved
    • Priority: Major - P3
    • None
    • Affects Version/s: None
    • Component/s: Aggregation Framework
    • None
    • Query Optimization
    • None
    • None
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      Like below code:

      db.test.aggregate([
  {
    "$facet": {
      "allGroups": [
        {
          "$facet": {
            "group1": [{
              "$group":{"_id": "$item1"}
            }],
            "group2": [{
              "$group":{"_id": "$item2"}
            }]
          }
        }
      ],
      "size": [
        {
          "$count": "size"
        }
      ]
    }
  }
])

      This will thrown:

      "errmsg" : "specified stage is not allowed to be used within a $facet stage: 0: { $facet: { group1: [ { $group:

      Unknown macro: { _id}

      } ], group2: [ { $group:

      Unknown macro: { _id}

      } ] } }",
      "code" : 40331,
      "codeName" : "Location40331"

      Hope to allow nested $facet happen, is there any downside?

            Assignee:
            [DO NOT USE] Backlog - Query Optimization
            Reporter:
            Jame Yang
            Votes:
            7 Vote for this issue
            Watchers:
            16 Start watching this issue

              Created:
              Updated: