Neptune Streams API Response Format - Amazon Neptune
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Neptune Streams API Response Format

A response to a Neptune Streams REST API request has the following fields:

  • lastEventId   –   Sequence identifier of the last change in the stream response. An event ID is composed of two fields: A commitNum identifies a transaction that changed the graph, and an opNum identifies a specific operation within that transaction. This is shown in the following example.

      "eventId": {
    "commitNum": 12,
    "opNum": 1
  }

  • lastTrxTimestamp   –   The time at which the commit for the transaction was requested, in milliseconds from the Unix epoch.

  • format   –   Serialization format for the change records being returned. The possible values are PG_JSON for Gremlin or openCypher change records, and NQUADS for SPARQL change records.

  • records   –   An array of serialized change-log stream records included in the response. Each record in the records array contains these fields:

    • commitTimestamp   –   The time at which the commit for the transaction was requested, in milliseconds from the Unix epoch.

    • eventId   –   The sequence identifier of the stream change record.

    • data   –   The serialized Gremlin, SPARQL, or OpenCypher change record. The serialization formats of each record are described in more detail in the next section, Serialization Formats in Neptune Streams.

    • op   –   The operation that created the change.

    • isLastOp   –   Only present if this operation is the last one in its transaction. When present, it is set to true. Useful for ensuring that an entire transaction is consumed.

  • totalRecords   –   The total number of records in the response.

For example, the following response returns Gremlin change data, for a transaction that contains more than one operation:

{
  "lastEventId": {
    "commitNum": 12,
    "opNum": 1
  },
  "lastTrxTimestamp": 1560011610678,
  "format": "PG_JSON",
  "records": [
    {
      "commitTimestamp": 1560011610678,
      "eventId": {
        "commitNum": 1,
        "opNum": 1
      },
      "data": {
        "id": "d2b59bf8-0d0f-218b-f68b-2aa7b0b1904a",
        "type": "vl",
        "key": "label",
        "value": {
          "value": "vertex",
          "dataType": "String"
        }
      },
      "op": "ADD"
    }
  ],
  "totalRecords": 1
}

The following response returns SPARQL change data for the last operation in a transaction (the operation identified by EventId(97, 1) in transaction number 97).

{
  "lastEventId": {
    "commitNum": 97,
    "opNum": 1
  },
  "lastTrxTimestamp": 1561489355102,
  "format": "NQUADS",
  "records": [
    {
      "commitTimestamp": 1561489355102,
      "eventId": {
        "commitNum": 97,
        "opNum": 1
      },
      "data": {
        "stmt": "<https://test.com/s> <https://test.com/p> <https://test.com/o> .\n"
      },
      "op": "ADD",
      "isLastOp": true
    }
  ],
  "totalRecords": 1
}