A relational workload runs intermittently: busy for a few hours, then idle for long stretches. The company wants to stop paying for always-on database capacity while keeping a relational engine. Which option fits best?
Aurora Serverless scales relational database capacity up and down automatically with demand, so an intermittent workload does not pay for capacity while idle — matching 'relational engine, no always-on cost'. Why not the others: a large always-on RDS instance is exactly the always-on cost the requirement wants to avoid. DynamoDB is NoSQL, so it abandons the relational requirement. Self-managing the database on EC2 adds operational burden and still runs continuously. Variable relational workloads point to Aurora Serverless.