PACELC Theorem

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Extends CAP: if there is a Partition, choose between Availability and Consistency (PAC); Else, when running normally, choose between Latency and Consistency (ELC). This captures the reality that even without partitions, there is a tradeoff between response time and consistency strength.

Key Properties

• Partition Tradeoff
• Latency vs Consistency
• Normal Operation Tradeoffs

Related

• CAP Theorem (PACELC extends CAP)
• Eventual Consistency (often chosen for lower latency)

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distributed-systems fundamentals