Skip to main content

CAP Theorem & Consistency Models

Difficulty: Medium | Topic #13

What to Learn

CAP theorem tradeoffs (Consistency, Availability, Partition Tolerance), strong consistency vs eventual consistency, read-your-writes, monotonic reads, linearizability, when to choose AP vs CP systems.

Resources

Covered by Problems

ProblemDifficultyLink
Distributed CacheMedium
Ticketing System (Ticketmaster)Medium
Online AuctionMedium
Payment SystemHard
Real-time Doc Collaboration (Google Docs)Hard

Key Concepts to Master

  • Why partition tolerance is mandatory in distributed systems
  • CP vs AP design choices and examples (HBase vs Cassandra)
  • Eventual consistency models (read-your-writes, monotonic reads, causal consistency)
  • Linearizability vs serializability
  • PACELC theorem as a more nuanced view