I started with the trip lifecycle which felt natural but in hindsight I should've anchored on the geo-spatial layer first since that's clearly where the interesting tradeoffs live.
Start by clarifying functional and non-functional requirements, then sketch a high-level architecture covering the main components: rider/driver apps, matching service, location tracking, trip management, pricing, and payment. Dive into the critical components like geospatial indexing for driver matching, real-time location updates, and consistency models for trip state and payments.
Pro tip: Emphasize trade-offs between consistency and availability, especially for location tracking and payment processing, and discuss how you would handle edge cases like driver cancellations or payment failures. Show awareness of Oracle's strengths in database and cloud infrastructure by mentioning how you might leverage their technologies for scalability and reliability.
Ask questions to understand expected scale, latency requirements, consistency needs, and key features. Define functional requirements (e.g., driver matching, real-time tracking) and non-functional requirements (e.g., scalability, availability).
Outline the main components: client apps, API gateway, matching service, location service, trip service, pricing engine, payment service, and databases. Explain how they interact and the data flow.
Detail driver matching using geospatial indexing (e.g., geohash, Quadtree) and real-time location tracking with WebSockets or MQTT. Discuss trip lifecycle state machine and consistency models.
Explain dynamic pricing algorithms (surge pricing) and payment processing with idempotency, retries, and integration with payment gateways. Discuss consistency and fault tolerance.
Discuss partitioning, replication, caching, and handling failures. Highlight trade-offs like consistency vs. availability, and how to ensure low latency at scale.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.