Consensus · 1998 · Leslie Lamport

The Part-Time Parliament

Build consensus safety from intersecting majorities and rules restricting what a proposer may choose, allowing failure to delay progress without choosing conflicting values.

The central move

Build consensus safety from intersecting majorities and rules restricting what a proposer may choose, allowing failure to delay progress without choosing conflicting values.

Why it had to exist

Replicated services need one decision despite crashes, delay, duplication, and reordering. Simple majority voting is insufficient when rounds overlap and participants recover.

Where it leads

Consensus proof → replicated logs → coordination services and strongly consistent distributed databases.

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