# GetPropertygraphStream


Gets a stream for a property graph.

With the Neptune Streams feature, you can generate a complete sequence of change-log entries that record every change made to your graph data as it happens. `GetPropertygraphStream` lets you collect these change-log entries for a property graph.

The Neptune streams feature needs to be enabled on your Neptune DBcluster. To enable streams, set the [neptune\$1streams](https://docs.amazonaws.cn/neptune/latest/userguide/parameters.html#parameters-db-cluster-parameters-neptune_streams) DB cluster parameter to `1`.

See [Capturing graph changes in real time using Neptune streams](https://docs.amazonaws.cn/neptune/latest/userguide/streams.html).

When invoking this operation in a Neptune cluster that has IAM authentication enabled, the IAM user or role making the request must have a policy attached that allows the [neptune-db:GetStreamRecords](https://docs.amazonaws.cn/neptune/latest/userguide/iam-dp-actions.html#getstreamrecords) IAM action in that cluster.

When invoking this operation in a Neptune cluster that has IAM authentication enabled, the IAM user or role making the request must have a policy attached that enables one of the following IAM actions, depending on the query:

Note that you can restrict property-graph queries using the following IAM context keys:
+  [neptune-db:QueryLanguage:Gremlin](https://docs.amazonaws.cn/neptune/latest/userguide/iam-data-condition-keys.html#iam-neptune-condition-keys) 
+  [neptune-db:QueryLanguage:OpenCypher](https://docs.amazonaws.cn/neptune/latest/userguide/iam-data-condition-keys.html#iam-neptune-condition-keys) 

See [Condition keys available in Neptune IAM data-access policy statements](https://docs.amazonaws.cn/neptune/latest/userguide/iam-data-condition-keys.html)).

## Request Syntax


```
GET /propertygraph/stream?commitNum=commitNum&iteratorType=iteratorType&limit=limit&opNum=opNum HTTP/1.1
Accept-Encoding: encoding
```

## URI Request Parameters


The request uses the following URI parameters.

 ** [commitNum](#API_GetPropertygraphStream_RequestSyntax) **   <a name="neptunedata-GetPropertygraphStream-request-uri-commitNum"></a>
The commit number of the starting record to read from the change-log stream. This parameter is required when `iteratorType` is`AT_SEQUENCE_NUMBER` or `AFTER_SEQUENCE_NUMBER`, and ignored when `iteratorType` is `TRIM_HORIZON` or `LATEST`.

 ** [encoding](#API_GetPropertygraphStream_RequestSyntax) **   <a name="neptunedata-GetPropertygraphStream-request-encoding"></a>
If set to TRUE, Neptune compresses the response using gzip encoding.  
Valid Values: `gzip` 

 ** [iteratorType](#API_GetPropertygraphStream_RequestSyntax) **   <a name="neptunedata-GetPropertygraphStream-request-uri-iteratorType"></a>
Can be one of:  
+  `AT_SEQUENCE_NUMBER`   –   Indicates that reading should start from the event sequence number specified jointly by the `commitNum` and `opNum` parameters.
+  `AFTER_SEQUENCE_NUMBER`   –   Indicates that reading should start right after the event sequence number specified jointly by the `commitNum` and `opNum` parameters.
+  `TRIM_HORIZON`   –   Indicates that reading should start at the last untrimmed record in the system, which is the oldest unexpired (not yet deleted) record in the change-log stream.
+  `LATEST`   –   Indicates that reading should start at the most recent record in the system, which is the latest unexpired (not yet deleted) record in the change-log stream.
Valid Values: `AT_SEQUENCE_NUMBER | AFTER_SEQUENCE_NUMBER | TRIM_HORIZON | LATEST` 

 ** [limit](#API_GetPropertygraphStream_RequestSyntax) **   <a name="neptunedata-GetPropertygraphStream-request-uri-limit"></a>
Specifies the maximum number of records to return. There is also a size limit of 10 MB on the response that can't be modified and that takes precedence over the number of records specified in the `limit` parameter. The response does include a threshold-breaching record if the 10 MB limit was reached.  
The range for `limit` is 1 to 100,000, with a default of 10.  
Valid Range: Minimum value of 1. Maximum value of 100000.

 ** [opNum](#API_GetPropertygraphStream_RequestSyntax) **   <a name="neptunedata-GetPropertygraphStream-request-uri-opNum"></a>
The operation sequence number within the specified commit to start reading from in the change-log stream data. The default is `1`.

## Request Body


The request does not have a request body.

## Response Syntax


```
HTTP/1.1 200
Content-type: application/json

{
   "format": "string",
   "lastEventId": { 
      "string" : "string" 
   },
   "lastTrxTimestamp": number,
   "records": [ 
      { 
         "commitTimestamp": number,
         "data": { 
            "from": "string",
            "id": "string",
            "key": "string",
            "to": "string",
            "type": "string",
            "value": JSON value
         },
         "eventId": { 
            "string" : "string" 
         },
         "isLastOp": boolean,
         "op": "string"
      }
   ],
   "totalRecords": number
}
```

## Response Elements


If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

 ** [format](#API_GetPropertygraphStream_ResponseSyntax) **   <a name="neptunedata-GetPropertygraphStream-response-format"></a>
Serialization format for the change records being returned. Currently, the only supported value is `PG_JSON`.  
Type: String

 ** [lastEventId](#API_GetPropertygraphStream_ResponseSyntax) **   <a name="neptunedata-GetPropertygraphStream-response-lastEventId"></a>
Sequence identifier of the last change in the stream response.  
An event ID is composed of two fields: a `commitNum`, which identifies a transaction that changed the graph, and an `opNum`, which identifies a specific operation within that transaction:  
Type: String to string map

 ** [lastTrxTimestamp](#API_GetPropertygraphStream_ResponseSyntax) **   <a name="neptunedata-GetPropertygraphStream-response-lastTrxTimestamp"></a>
The time at which the commit for the transaction was requested, in milliseconds from the Unix epoch.  
Type: Long

 ** [records](#API_GetPropertygraphStream_ResponseSyntax) **   <a name="neptunedata-GetPropertygraphStream-response-records"></a>
An array of serialized change-log stream records included in the response.  
Type: Array of [PropertygraphRecord](API_PropertygraphRecord.md) objects

 ** [totalRecords](#API_GetPropertygraphStream_ResponseSyntax) **   <a name="neptunedata-GetPropertygraphStream-response-totalRecords"></a>
The total number of records in the response.  
Type: Integer

## Errors


For information about the errors that are common to all actions, see [Common Error Types](CommonErrors.md).

 ** ClientTimeoutException **   
Raised when a request timed out in the client.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request in question.
HTTP Status Code: 408

 ** ConstraintViolationException **   
Raised when a value in a request field did not satisfy required constraints.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request in question.
HTTP Status Code: 400

 ** ExpiredStreamException **   
Raised when a request attempts to access an stream that has expired.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request in question.
HTTP Status Code: 400

 ** IllegalArgumentException **   
Raised when an argument in a request is not supported.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request in question.
HTTP Status Code: 400

 ** InvalidArgumentException **   
Raised when an argument in a request has an invalid value.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request in question.
HTTP Status Code: 400

 ** InvalidParameterException **   
Raised when a parameter value is not valid.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request that includes an invalid parameter.
HTTP Status Code: 400

 ** MemoryLimitExceededException **   
Raised when a request fails because of insufficient memory resources. The request can be retried.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request that failed.
HTTP Status Code: 500

 ** PreconditionsFailedException **   
Raised when a precondition for processing a request is not satisfied.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request in question.
HTTP Status Code: 400

 ** StreamRecordsNotFoundException **   
Raised when stream records requested by a query cannot be found.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request in question.
HTTP Status Code: 404

 ** ThrottlingException **   
Raised when the rate of requests exceeds the maximum throughput. Requests can be retried after encountering this exception.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request that could not be processed for this reason.
HTTP Status Code: 500

 ** TooManyRequestsException **   
Raised when the number of requests being processed exceeds the limit.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request that could not be processed for this reason.
HTTP Status Code: 429

 ** UnsupportedOperationException **   
Raised when a request attempts to initiate an operation that is not supported.    
 ** code **   
The HTTP status code returned with the exception.  
 ** detailedMessage **   
A detailed message describing the problem.  
 ** requestId **   
The ID of the request in question.
HTTP Status Code: 400

## See Also


For more information about using this API in one of the language-specific Amazon SDKs, see the following:
+  [Amazon Command Line Interface V2](https://docs.amazonaws.cn/goto/cli2/neptunedata-2023-08-01/GetPropertygraphStream) 
+  [Amazon SDK for .NET V4](https://docs.amazonaws.cn/goto/DotNetSDKV4/neptunedata-2023-08-01/GetPropertygraphStream) 
+  [Amazon SDK for C\$1\$1](https://docs.amazonaws.cn/goto/SdkForCpp/neptunedata-2023-08-01/GetPropertygraphStream) 
+  [Amazon SDK for Go v2](https://docs.amazonaws.cn/goto/SdkForGoV2/neptunedata-2023-08-01/GetPropertygraphStream) 
+  [Amazon SDK for Java V2](https://docs.amazonaws.cn/goto/SdkForJavaV2/neptunedata-2023-08-01/GetPropertygraphStream) 
+  [Amazon SDK for JavaScript V3](https://docs.amazonaws.cn/goto/SdkForJavaScriptV3/neptunedata-2023-08-01/GetPropertygraphStream) 
+  [Amazon SDK for Kotlin](https://docs.amazonaws.cn/goto/SdkForKotlin/neptunedata-2023-08-01/GetPropertygraphStream) 
+  [Amazon SDK for PHP V3](https://docs.amazonaws.cn/goto/SdkForPHPV3/neptunedata-2023-08-01/GetPropertygraphStream) 
+  [Amazon SDK for Python](https://docs.amazonaws.cn/goto/boto3/neptunedata-2023-08-01/GetPropertygraphStream) 
+  [Amazon SDK for Ruby V3](https://docs.amazonaws.cn/goto/SdkForRubyV3/neptunedata-2023-08-01/GetPropertygraphStream)