Plan a major database version upgrade
Company: Turo
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
You have an application tier (API/web servers) talking to a primary database for writes and a secondary/replica database for reads. You need to perform a major DB version upgrade (e.g., v13 → v15).
Design an upgrade plan that addresses:
- Downtime vs near-zero-downtime approaches
- Data migration strategy (in-place vs new cluster)
- Cutover strategy (how to switch reads/writes)
- Whether to use dual-write or change-data-capture
- Compatibility concerns (SQL/features/drivers)
- Rollback plan
- Trade-offs: cost, consistency, risk, and impact to the business
Quick Answer: This question evaluates competency in database upgrade planning, including data migration strategies, cutover coordination, compatibility considerations, change-data-capture versus dual-write trade-offs, and rollback and risk management.