CAP Theorem in Practice
What common mistakes do candidates make around CAP Theorem in Practice, and how do you avoid them?
Answers use simple, clear English.
Audio N/AQuick interview answer
Common mistakes: Claiming CA without partition definition. Best practices: Name concrete choice per feature; mention quorum reads.
Detailed answer
Common mistakes: Claiming CA without partition definition. Best practices: Name concrete choice per feature; mention quorum reads. Core: Under partition, choose Consistency or Availability (CP vs AP). Most systems are PA with tunable consistency. PACELC extends with latency trade-off. Real-time example: Bank balance during partition: CP (reject writes). Social feed likes: AP (eventual counts). Pros: Frames trade-offs for interviews clearly. Cons: Oversimplified — real systems offer levels not binary. Common mistakes: Claiming CA without partition definition. Best practices: Name concrete choice per feature; mention quorum reads. Audience level: Fresher.
Full explanation
Under partition, choose Consistency or Availability (CP vs AP). Most systems are PA with tunable consistency. PACELC extends with latency trade-off.
Real example & use case
Bank balance during partition: CP (reject writes). Social feed likes: AP (eventual counts).
Pros & cons
Pros: Frames trade-offs for interviews clearly. Cons: Oversimplified — real systems offer levels not binary.
Common mistakes
Claiming CA without partition definition.
Best practices
Name concrete choice per feature; mention quorum reads.
Follow-up questions
- How would you test CAP Theorem in Practice?
- What metrics prove CAP Theorem in Practice is healthy in prod?
- How does CAP Theorem in Practice change at 10× traffic?