Use Connection: keep-alive to improve application performance

[milancermak]

By default, NodeJS sets Connection: close and not Connection: keep-alive HTTP header which results in sub-optimal performance. Instead of reusing an already established connection between the client and the service, a new one has to be created for every operation.

It has been reported before (#146), recently publicized by an AWS Serverless Hero and it's also recommended by AWS for DynamoDB when using encryption at rest. DynamoDB itself responds with a Connection: keep-alive header.

Even though all these examples pertain to DynamoDB, I imagine other services will benefit from this change as well. For what it's worth, boto3, the official AWS SDK for Python does not explicitly set a Connection: close header.

Please consider setting keep-alive header the on the SDK level so that going forward, the whole community can benefit from this improvement.

[srchase]

Changing the default behavior here could introduce issues for existing users of the SDK. If this were enabled by default, it would require a major version bump.

It is possible to enable keep-alive through configuration.

That can be done on the global config:

const AWS = require('aws-sdk')
const https = require('https');
const agent = new https.Agent({
  keepAlive: true
})

AWS.config.update({
  httpOptions: {
    agent: agent
  }
})

Or on a per-client basis:

const AWS = require('aws-sdk')
const https = require('https');
const agent = new https.Agent({
  keepAlive: true
});

const DDB = new AWS.DynamoDB({
  httpOptions: {
    agent: agent
  }
});

[github-actions]

Greetings! We’re closing this issue because it has been open a long time and hasn’t been updated in a while and may not be getting the attention it deserves. We encourage you to check if this is still an issue in the latest release and if you find that this is still a problem, please feel free to comment or open a new issue.

[Aleksandr-Filichkin]

Just to understand the difference
Aleksandr-Filichkin/aws-lambda-runtimes-performance#6 (comment)