This document provides an overview of use case scenarios for ProxySQL, a database proxy that can improve scalability, high availability, and manageability of MySQL database operations. It describes how ProxySQL can be used for connection pooling and sharding to improve scalability, seamless failover and load balancing for high availability, and advanced query capabilities like caching, rewriting, and throttling queries. The document also provides examples of how companies have implemented ProxySQL to reduce load on databases and handle heavy workloads.