Comment by andrew_k

If you are creating connections outside of handler, it gets cached by Lambda between invocations. However you'll need to tune your database settings or you'll run out of connections on traffic spikes. Depends on your pattern of usage. Also cold start of lambda in VPC could take around 15 seconds https://www.reddit.com/r/aws/comments/49l91l/lambda_function... https://forums.aws.amazon.com/thread.jspa?messageID=735318&t... My experience with DynamoDb was much smoother than with Postgres RDS in VPC