RDSDataService "Communications link failure" when unpausing

Confirm by changing [ ] to [x] below to ensure that it’s a bug:

• I’ve gone though Developer Guide and API reference
• I’ve checked AWS Forums and StackOverflow* for answers
• I’ve searched for previous similar issues and didn’t find any solution

Describe the bug

Running AWS.RDSDataService.executeStatement against a auto-paused Serverless Aurora instance results in the following, unhandled, error:

BadRequestException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at Object.extractError (/Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/protocol/json.js:51:27)
    at Request.extractError (/Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/protocol/rest_json.js:55:8)
    at Request.callListeners (/Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/sequential_executor.js:106:20)
    at Request.emit (/Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/sequential_executor.js:78:10)
    at Request.emit (/Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/request.js:683:14)
    at Request.transition (/Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/request.js:22:10)
    at AcceptorStateMachine.runTo (/Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/state_machine.js:14:12)
    at /Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/state_machine.js:26:10
    at Request.<anonymous> (/Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/request.js:38:9)
    at Request.<anonymous> (/Users/michael/Work/scratch/mysql/node_modules/aws-sdk/lib/request.js:685:12)

Apparently the Communications link failure is expected while compute is being automatically re-provisioned (see additional context), and the client is expected to retry with a delay.

Is the issue in the browser/Node.js? Node.js

If on Node.js, are you running this on AWS Lambda? Issue can be reproduced on local machine.

Details of the browser/Node.js version v12.13.0

SDK version number Example: v2.553.0

To Reproduce (observed behavior)

1. Create a Serverless Aurora cluster instructions
2. With the “pause compute capacity after consecutive minutes of inactivity” set to the minimum of 5 minutes
3. Once commissioned wait 5-10 minutes for Aurora to scale to 0 capacity units (i.e. paused).
4. Run minimal query script below (replacing ARNs as required) - it will fail with the error reported above.
5. Wait ~30-60 seconds and re-run the query script - it will return a result.

import AWS from 'aws-sdk';

const db = new AWS.RDSDataService({ region: 'eu-west-1' });

async function main() {
  const sql = ;
  const result = await db
    .executeStatement({
      sql: 'select * from information_schema.tables;',
      resourceArn: 'DATABASE_ARN',
      secretArn: 'CONNECTION_SECRET_ARN',
    })
    .promise();
  console.log(JSON.stringify(result, null, 2));
}
main();

Expected behavior

I expected the aws-sdk to retry with a delay after receiving the BadRequestException.

Additional context

*A search across StackOverflow found a response from AWS support that the failure itself is expected behaviour (https://stackoverflow.com/questions/58192747/aws-aurora-serverless-communication-link-failure).

Clients are expected to wait and retry.

[thomasmichaelwallace]

Cool - @ajredniwja - I’ve given it a go. See #2931

[lock[bot]]

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