MySQL follows a layered architecture that separates client connections, SQL processing, and physical storage. Knowing how a query travels through these layers helps data professionals write faster queries and debug performance issues scientifically.
Key Points
- Connection layer: handles client authentication, sessions, and thread management
- SQL layer: parser, optimiser, and caches that decide the best execution plan
- Storage engine layer: pluggable engines (InnoDB, MyISAM, Memory) that read and write data
- Query flow: connect → parse → optimise → execute → return results
- InnoDB adds buffer pool, redo logs, and undo logs for reliability
Data scientists working with large datasets benefit from understanding the optimiser and buffer pool — they explain why some queries run in milliseconds while others crawl.