Amazon DynamoDB is a fully managed NoSQL database service provided by AWS, offering a scalable and high-performance data management solution. However, as a managed service, it requires vigilant monitoring to ensure optimal performance and troubleshoot common issues such as limited visibility, permissions, code debugging, and exception handling. Key metrics to monitor include throttled requests, latency, errors, capacity, and performance metrics like ConsumedReadCapacityUnits, ConsumedWriteCapacityUnits, ReadThrottleEvents, WriteThrottleEvents, SystemErrors, and UserErrors. To optimize DynamoDB for performance, it's essential to monitor read and write capacity usage, choose between on-demand and provisioned instances based on traffic expectations, enable autoscaling, and design applications to utilize DynamoDB's features effectively.