System Design Interview: Design Uber w/ a Ex-Meta Staff Engineer

Step-by-Step Tutorial: Designing Uber System

1. Understand the Requirements:

• Identify the functional requirements of the system, such as users inputting start and destination locations to get an estimated fare, requesting a ride, and drivers accepting or denying ride requests.
• Determine non-functional requirements like low latency, consistency of matching, high availability, and handling high throughput surges.

2. Define Core Entities and API:

• Core entities include the location entity for drivers and people entity for users.
• APIs like getting fare estimates, requesting rides, driver acceptance, and navigation to pick-up/drop-off locations need to be designed.

3. High-Level Design:

• Use AWS API Gateway to route requests to microservices like Ride Service for fare estimates and Matching Service for driver-rider matching.
• Implement a third-party mapping service like Google Maps for estimating ride prices.
• Utilize a primary database to persist ride data and a separate service for asynchronous processes like matching.

4. Deep Dive - Low Latency Matching:

• Optimize location services using geospatial indexes like Quad Trees or GeoHashing to efficiently query driver locations.
• Implement a distributed lock mechanism using Redis or DynamoDB to ensure drivers are not double-booked.

5. Deep Dive - Consistency of Matching:

• Use logical checks within the ride matching service to prevent assigning multiple rides to a driver simultaneously.
• Employ a distributed lock or a separate database table to manage driver availability and prevent race conditions.

6. Deep Dive - Handling High Throughput Surges:

• Scale the system by introducing a ride request queue partitioned by regions to handle surges and ensure high availability.
• Consider horizontal scaling by replicating the system setup across multiple data centers to improve availability and reduce strain on the system.

7. Conclusion:

• Review and refine the design to ensure it meets all functional and non-functional requirements.
• Prepare to discuss the design decisions and optimizations made during the interview to showcase your system design skills effectively.

By following these steps and understanding the intricacies of designing a complex system like Uber, you can effectively prepare for system design interviews and demonstrate your expertise in handling real-world design challenges. Good luck with your upcoming interviews!