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# Document source exchange stage IDL file

global:
   cpp_namespace: "mongo"

imports:
    - "mongo/db/basic_types.idl"

enums:
    ExchangePolicy:
        description: "The type of an exchange distribution policy"
        type: string
        values:
            kBroadcast: "broadcast"
            kRoundRobin: "roundrobin"
            kKeyRange: "keyRange"

structs:
  ExchangeSpec:
    description: "exchange aggregation request specification"
    query_shape_component: true
    fields:
      policy:
        type: ExchangePolicy
        description: A string indicating a policy of how documents are distributed to consumers.
        stability: stable
        query_shape: parameter
      consumers:
        type: int
        description: Number of consumers.
        stability: stable
        query_shape: literal
      orderPreserving:
        type: bool
        default: false
        description: A flag indicating documents are merged while preserving the order.
        stability: stable
        query_shape: parameter
      bufferSize:
        type: int
        default: 16777216
        description: The size of exchange buffers.
        stability: stable
        query_shape: literal
      key:
        type: object
        default: "BSONObj()"
        stability: stable
        description: A key used for document distribution to consumers. The same description as
                     sorting/sharding. If the document entering the exchange does not have every
                     field listed here, or if any prefix of any path is multikey (i.e. an array is
                     encountered while traversing a path listed here), then it is by definition sent
                     to consumer 0.
        query_shape: literal
      boundaries:
        type: array<object>
        optional: true
        description: Range/hash split points.
        stability: stable
        query_shape: literal
      consumerIds:
        type: array<int>
        optional: true
        description: Mapping from a range index to a consumer id.
        stability: stable
        query_shape: literal