Problem: Design Flight Booking and Real-Time Voting Systems
This interview consists of two distinct system design challenges. Please address both parts comprehensively.
Part A: Flight Ticket Booking System
Design the backend infrastructure for a flight ticket booking product. The system must support core functionalities including searching for available flights, allowing users to select an itinerary, processing ticket bookings for passengers, and critically, preventing overselling of seats.
Your design should cover the following aspects:
- Data Model: Define the data schema for key entities such as
Flight,Passenger, andFlightTicketorBooking. - Indexing Strategy: Propose appropriate database indexes and justify their necessity for efficient query performance.
- B-tree Internals: Explain the internal workings of B-tree indexes and discuss how this understanding influences your query design and optimization choices.
- End-to-End User Flow: Detail the complete user experience flow for booking a flight, from search to confirmation, along with the corresponding backend queries involved at each step.
- Concurrency Control: Describe mechanisms to prevent double booking or overselling of seats when multiple users attempt to purchase the same flight or seat concurrently.
Part B: Real-Time High-QPS Voting System
Design a real-time voting system to support a fast-food promotion during a major live event. Users should be able to quickly cast a vote for a specific taco flavor, and a live results board must display the aggregated votes in near real-time.
Key requirements for this system include:
- High Throughput: The system must handle traffic spikes reaching several million votes per second for short durations.
- Low Latency: Individual vote actions should be processed with minimal latency.
- Near Real-Time Updates: The results board must reflect vote counts with minimal delay.
- Reliability: The design must remain stable and reliable even under sudden, extreme traffic spikes.
Your design should address the following technical considerations:
- Architecture: Outline the APIs, services, storage solutions, and overall data flow.
- Durable Streaming: Explain how a system like Apache Kafka or another durable streaming platform would be integrated and utilized.
- Real-time Metrics: Detail how real-time counters and time-series metrics would be modeled and managed.
- Internal Mechanisms: Discuss relevant internals of Kafka and time-series databases that inform your design choices.
- Deployment & Scaling: Describe a deployment strategy using Kubernetes or EKS, including considerations for autoscaling to handle fluctuating load.
AI interview prep
Core dilemma
Navigating the fundamental architectural differences between strong transactional consistency for critical financial operations (flight booking) and extreme scale, low-latency, eventually consistent real-time data processing (voting system). The challenge lies in demonstrating proficiency across both paradigms and articulating their distinct trade-offs.
3 tradeoffs and 3 stress tests locked
Interview prep
Unlock the interviewer X-Ray rubric, tradeoff matrix, stress tests, clarifying questions, and key concepts.
Problem: Design Flight Booking and Real-Time Voting Systems
This interview consists of two distinct system design challenges. Please address both parts comprehensively.
Part A: Flight Ticket Booking System
Design the backend infrastructure for a flight ticket booking product. The system must support core functionalities including searching for available flights, allowing users to select an itinerary, processing ticket bookings for passengers, and critically, preventing overselling of seats.
Your design should cover the following aspects:
- Data Model: Define the data schema for key entities such as
Flight,Passenger, andFlightTicketorBooking. - Indexing Strategy: Propose appropriate database indexes and justify their necessity for efficient query performance.
- B-tree Internals: Explain the internal workings of B-tree indexes and discuss how this understanding influences your query design and optimization choices.
- End-to-End User Flow: Detail the complete user experience flow for booking a flight, from search to confirmation, along with the corresponding backend queries involved at each step.
- Concurrency Control: Describe mechanisms to prevent double booking or overselling of seats when multiple users attempt to purchase the same flight or seat concurrently.
Part B: Real-Time High-QPS Voting System
Design a real-time voting system to support a fast-food promotion during a major live event. Users should be able to quickly cast a vote for a specific taco flavor, and a live results board must display the aggregated votes in near real-time.
Key requirements for this system include:
- High Throughput: The system must handle traffic spikes reaching several million votes per second for short durations.
- Low Latency: Individual vote actions should be processed with minimal latency.
- Near Real-Time Updates: The results board must reflect vote counts with minimal delay.
- Reliability: The design must remain stable and reliable even under sudden, extreme traffic spikes.
Your design should address the following technical considerations:
- Architecture: Outline the APIs, services, storage solutions, and overall data flow.
- Durable Streaming: Explain how a system like Apache Kafka or another durable streaming platform would be integrated and utilized.
- Real-time Metrics: Detail how real-time counters and time-series metrics would be modeled and managed.
- Internal Mechanisms: Discuss relevant internals of Kafka and time-series databases that inform your design choices.
- Deployment & Scaling: Describe a deployment strategy using Kubernetes or EKS, including considerations for autoscaling to handle fluctuating load.