May 28, 2023 7:00 PM PDT
The meeting focused on the design and functional requirements of a Hotel Reservation System. Key discussions included the architecture, database design, transaction management, and handling of booking operations. The aim was to create a robust system capable of managing high volumes of bookings efficiently.
Meeting Details
- Interviewer: new / xiaoge
- Level: L5 (Senior)
Agenda
1. Gathering Requirements
- Discussed functional requirements and background information.
- Calculated booking speed: 4 million bookings per day translates to approximately 40 bookings per second.
2. High-Level Design
- Introduced a hotel information service for searching hotel rooms.
3. Database Design
- Identified key databases:
- Payment DB
- Room DB
- Hotel DB
- Room Time Slot DB
- Discussed potential to combine databases and utilize multiple tables.
- Hotel Info Service:
- Hotel DB
- Room DB
- Room Service:
- Room Time Slot DB
- Considered the need for caching to improve query performance.
4. Reservation Process
- Discussed the reservation database and its structure.
- Walked through the reservation process:
- Booking service records reservation in the reservation DB.
- Booking service requests available rooms from room service.
- Booking service makes requests to both room service and payment service, requiring rollback if either fails.
5. Distributed Transaction Management
- Explored three alternatives for ensuring distributed transactions:
- Two-Phase Commit: Requires database support for locking.
- Try-and-Cancel: Each service commits independently; booking service undoes changes if any service fails.
- Saga Pattern: Sequential command execution with rollback capabilities for failed steps. Chose Saga for implementation.
6. Database Changes
- Changes to the reservation table to set status to pending.
- Logging actions at each step of the process to ensure traceability.
7. Handling Concurrent Bookings
- Discussed strategies for managing simultaneous bookings and the lifecycle of services.
- Considered combining services and databases for efficiency while maintaining branding.
8. Additional Requirements
- Potential to extend the system to include distribution of hotel images/videos and support for property management.
Conclusion
The meeting concluded with a clear understanding of the system's architecture, database design, and transaction management strategies. The next steps involve further refining the design and addressing any additional requirements.