Question

A developer maintains a Node.js Lambda function that makes many outbound HTTPS calls to a downstream REST API during each invocation. X-Ray traces show that a significant portion of each request's latency is spent establishing new TLS connections for every call. The function reuses the same HTTP client library across calls within an invocation. What is the MOST effective change to reduce this connection-establishment overhead?

Accepted Answer

Enable HTTP keep-alive on the HTTPS agent so TCP/TLS connections are reused across requests instead of being renegotiated each time.

Answer

Increase the Lambda function's memory allocation to speed up the TLS handshake computation.

Answer

Move the function into a VPC with a NAT gateway so outbound connections are pooled by the gateway.

Answer

Enable provisioned concurrency so the TLS sessions remain warm between invocations.