Request Syntax URI Request Parameters Request Body Response Syntax Response Elements Errors See Also

ExecuteGremlinExplainQuery

Executes a Gremlin Explain query.

Amazon Neptune has added a Gremlin feature named explain that provides is a self-service tool for understanding the execution approach being taken by the Neptune engine for the query. You invoke it by adding an explain parameter to an HTTP call that submits a Gremlin query.

The explain feature provides information about the logical structure of query execution plans. You can use this information to identify potential evaluation and execution bottlenecks and to tune your query, as explained in Tuning Gremlin queries. You can also use query hints to improve query execution plans.

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 one of the following IAM actions in that cluster, depending on the query:

Note that the neptune-db:QueryLanguage:Gremlin IAM condition key can be used in the policy document to restrict the use of Gremlin queries (see Condition keys available in Neptune IAM data-access policy statements).

Request Syntax


POST /gremlin/explain HTTP/1.1
Content-type: application/json

{
   "gremlin": "string"
}

URI Request Parameters

The request does not use any URI parameters.

Request Body

The request accepts the following data in JSON format.

gremlin

The Gremlin explain query string.

Type: String

Required: Yes

Response Syntax


HTTP/1.1 200

output

Response Elements

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

The response returns the following as the HTTP body.

output: A text blob containing the Gremlin explain result, as described in Tuning Gremlin queries.

Errors

For information about the errors that are common to all actions, see Common Errors.

BadRequestException

Raised when a request is submitted that cannot be processed.

HTTP Status Code: 400

CancelledByUserException

Raised when a user cancelled a request.

HTTP Status Code: 500

ClientTimeoutException

Raised when a request timed out in the client.

HTTP Status Code: 408

ConcurrentModificationException

Raised when a request attempts to modify data that is concurrently being modified by another process.

HTTP Status Code: 500

ConstraintViolationException

Raised when a value in a request field did not satisfy required constraints.

HTTP Status Code: 400

FailureByQueryException

Raised when a request fails.

HTTP Status Code: 500

IllegalArgumentException

Raised when an argument in a request is not supported.

HTTP Status Code: 400

InvalidArgumentException

Raised when an argument in a request has an invalid value.

HTTP Status Code: 400

InvalidParameterException

Raised when a parameter value is not valid.

HTTP Status Code: 400

MalformedQueryException

Raised when a query is submitted that is syntactically incorrect or does not pass additional validation.

HTTP Status Code: 400

MemoryLimitExceededException

Raised when a request fails because of insufficient memory resources. The request can be retried.

HTTP Status Code: 500

MissingParameterException

Raised when a required parameter is missing.

HTTP Status Code: 400

ParsingException

Raised when a parsing issue is encountered.

HTTP Status Code: 400

PreconditionsFailedException

Raised when a precondition for processing a request is not satisfied.

HTTP Status Code: 400

QueryLimitExceededException

Raised when the number of active queries exceeds what the server can process. The query in question can be retried when the system is less busy.

HTTP Status Code: 500

QueryLimitException

Raised when the size of a query exceeds the system limit.

HTTP Status Code: 400

QueryTooLargeException

Raised when the body of a query is too large.

HTTP Status Code: 400

TimeLimitExceededException

Raised when the an operation exceeds the time limit allowed for it.

HTTP Status Code: 500

TooManyRequestsException

Raised when the number of requests being processed exceeds the limit.

HTTP Status Code: 429

UnsupportedOperationException

Raised when a request attempts to initiate an operation that is not supported.

HTTP Status Code: 400