MySQL partitioning is a technique used to split large data into smaller chunks, improving performance and reducing storage needs. It involves dividing a table into partitions based on specific criteria, such as numerical ranges or fixed values, allowing for more efficient querying and maintenance operations. Partitioning provides benefits like faster query performance, reduced storage requirements, and simplified maintenance tasks, but it also has drawbacks, including limitations on data types and the need to properly understand access patterns. MySQL partitioning is a native feature of MySQL and can be used in conjunction with other scaling strategies, such as sharding, which involves splitting tables across multiple servers. While partitioning is not supported in PlanetScale due to its focus on horizontal scalability, it remains an important technique for improving database performance.