Query to AWS Neptune from Lambda via Bolt driver times out with no response

Question

My query from an AWS Lambda function (Javascript) to an AWS Neptune database, using the Bolt protocol (neo4j-driver) times out without returning a response. I've turned on debug mode and the connection appears to get created correctly and the query is executed and appears to complete but for some reason the promise from the "tx.run" call never completes and the action simply times out.

The test code looks like this:

const session = driver.session();
try {
    const result = await session.writeTransaction(tx =>
        tx.run(`MATCH (n) RETURN n`).then(result => {
            console.log('result', result)
        })
    )
} finally {
    await session.close()
}

The driver, with debug enabled, outputs the following (abbreviated for easier readability):

11:22:27.217 INFO driver created

11:22:27.477 INFO 1704482547477 DEBUG Connection [0][] created towards db-neptune-3.cluster-****.us-west-1.neptune.amazonaws.com:8182

11:22:27.478 INFO 1704482547478 DEBUG Connection [0][] C: HELLO {user_agent: 'neo4j-javascript/4.3.3', ...}

11:22:27.608 INFO 1704482547608 DEBUG Connection [0][] S: SUCCESS {"signature":112,"fields":[{"server":"Neo4j/4.2.0-compatible-by-amazon-neptune","connection_id":"4a5a5efffeb5714f-00005357-0000001f-c7d239b9e462a6c7-3d9eac5f"}]}

11:22:27.616 INFO 1704482547616 DEBUG Connection [0][4a5a5efffeb5714f-00005357-0000001f-c7d239b9e462a6c7-3d9eac5f] created for the pool db-neptune-3.cluster-****.us-west-1.neptune.amazonaws.com:8182

11:22:27.617 INFO 1704482547617 DEBUG Connection [0][4a5a5efffeb5714f-00005357-0000001f-c7d239b9e462a6c7-3d9eac5f] C: BEGIN {}

11:22:27.618 INFO 1704482547618 DEBUG Connection [0][4a5a5efffeb5714f-00005357-0000001f-c7d239b9e462a6c7-3d9eac5f] C: RUN MATCH (n) RETURN n {} {}

11:22:27.618 INFO 1704482547618 DEBUG Connection [0][4a5a5efffeb5714f-00005357-0000001f-c7d239b9e462a6c7-3d9eac5f] C: PULL {"n":{"low":1000,"high":0}}

11:22:27.656 INFO 1704482547656 DEBUG Connection [0][4a5a5efffeb5714f-00005357-0000001f-c7d239b9e462a6c7-3d9eac5f] S: SUCCESS {"signature":112,"fields":[{}]}

11:22:29.545 INFO 1704482549545 DEBUG Connection [0][4a5a5efffeb5714f-00005357-0000001f-c7d239b9e462a6c7-3d9eac5f] S: SUCCESS {"signature":112,"fields":[{"fields":["n"],"result_available_after":1841}]}

11:22:32.118 Task timed out after 5.04 seconds

The Lambda function has a 5 second timeout (longer timeout doesn't change this behavior). Is there something I've done wrong with the configuration between Lambda and Neptune that is causing a communication issue with the return result? Both the Lambda function and the Neptune DB are in the same VPC. As far as I can tell, it appears that the connection is being established correctly (i.e. authentication is working, etc), the query is being delivered to the server, executed, and results are pending. Thanks in advance for any help.

FYI - Neptune is run in "serverless" mode (engine version: 1.2.0.1). Using the 4.3.3 version of the javascript neo4j-driver.

I'm simply trying to get a basic CRUD test running between a Lambda function and a newly created Neptune database. I have a basic piece of test code attempting to run a query against the database and it appears to be getting delivered but for some reason the response is not being returned and/or received from Neptune to my Lambda function.

Answer 1

With the information provided, it is hard to say exactly what the issue is here.

How much data is in your graph? MATCH (n) RETURN n is going to return the entire graph is generally an antipattern as it will grow unpredictable and could easily take longer than 5 seconds. What happens if you just do RETURN 1?

The best practice when using Neptune Database with Lambda (https://docs.aws.amazon.com/neptune/latest/userguide/best-practices-opencypher.html#best-practices-opencypher-lambda-connections) is to not use the bolt driver and to use the HTTPS endpoint instead. The design of bolt is to persist a long-lived connection, which is an antipattern when using a serveless compute such as Lambda.

I would suggest using the AWS SDK for Javascript which supports executing openCypher commands: https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/neptunedata/command/ExecuteOpenCypherQueryCommand/