Add PostgreSQL Session Variable Tracking in ProxySQL

[rahim-kanji]

Description

ProxySQL currently does not support tracking session variables for PostgreSQL. Introducing this feature would greatly enhance session management and query routing, making ProxySQL more adaptable for PostgreSQL environments.

Importance of Session Variable Tracking:

Optimized Query Routing:

Session variables influence application logic and user configurations. Tracking these enables precise query routing to the most appropriate backend server.

Session Consistency:

Maintains session-specific configurations during failovers or backend changes, ensuring a seamless user experience.