NOTE
MySQL Connections and Connectors
Client authentication, sessions, connection pools, limits, timeouts, and protocol lifecycle.
This is a historical learning note and may contain outdated or incomplete understanding.
Clients connect to MySQL through a connector/driver implementing the MySQL protocol. A server session carries authentication identity and session state such as transaction, isolation, charset, and variables.
Application connection pools should be bounded and sized from database capacity, not application thread count. Configure connection/acquire/query timeouts, validate broken connections, and avoid thousands of idle sessions that consume resources without adding throughput.