juniorCAP Theorem
Why is 'P' (Partition Tolerance) usually considered mandatory?
Updated Apr 28, 2026
Short answer
Because network failures are inevitable in distributed systems; if you don't handle P, the system isn't truly distributed or robust.
Deep explanation
The CAP Theorem is a fundamental principle in distributed systems design. Because network failures are inevitable in distributed systems; if you don't handle P, the system isn't truly distributed or robust. It forces architects to acknowledge that trade-offs are unavoidable in wide-area networks.
Real-world example
A single-node relational database behaves as CA until it scales horizontally.
Common mistakes
- Thinking CAP applies to systems that aren't distributed (like a single-instance DB).
Follow-up questions
- Is CAP relevant for single-core apps?