cap-theorem-tradeoffslisted

# CAP-Theorem Tradeoffs ## Coverage The consistency-availability-partition-tolerance trade-off that physics imposes on distributed data systems. Covers Brewer's 2000 conjecture, Gilbert & Lynch's 2002 formal proof, why P is mandatory in real networks (the practical choice is CP vs AP, not "any two of three"), the PACELC extension (Abadi 2010) that names the latency-vs-consistency trade-off in the non-partition case, the CAP-C vs ACID-C confusion that is the most-common misconception in the space, the spectrum of consistency models from linearizability to eventual consistency, the four PACELC quadrants (PA/EL, PA/EC, PC/EL, PC/EC) and the systems that occupy each, and the partition-mode choice procedure. ## Philosophy CAP is the frame that made distributed-systems design honest. Before Brewer's 2000 conjecture and Gilbert & Lynch's 2002 proof, the industry made contradictory claims about consistency, availability, and fault tolerance; after CAP, those claims have shape. Under partition — which physics guarantees will happen — you preserve consistency at the cost of availability, or availability at the cost of consistency. The discipline is making the choice *per workload* and *intentionally*. A banking core ledger is right to be CP. A shopping cart's session state is right to be AP. A multi-region content-delivery system is right to be AP with eventual consistency. A schema registry is right to be CP. The choice is the engineering team's responsibility; CAP names the trad