Computational Consistency Model

A Computational Consistency Model is a formal model that defines data coherence guarantees in distributed systems.

• AKA: Data Consistency Model, Distributed Consistency Model, Coherence Model, Memory Consistency Model.
• Context:
  • It can typically specify Read-Write Ordering Rules through consistency protocols.
  • It can typically influence System Performance Metrics via synchronization overhead.
  • It can often determine Application Correctness Propertys through invariant maintenance.
  • It can often trade off Availability Propertys via CAP theorem constraints.
  • It can range from being a Strong Computational Consistency Model to being a Weak Computational Consistency Model, depending on its guarantee strength.
  • It can range from being a Pessimistic Computational Consistency Model to being an Optimistic Computational Consistency Model, depending on its conflict assumption.
  • It can range from being a Synchronous Computational Consistency Model to being an Asynchronous Computational Consistency Model, depending on its timing assumption.
  • It can range from being a Client-Centric Computational Consistency Model to being a Data-Centric Computational Consistency Model, depending on its perspective focus.
  • It can integrate with Distributed Computational Processes for data synchronization.
  • It can integrate with Transaction Management Systems for ACID compliance.
  • ...
• Examples:
  • Strong Consistency Models, such as:
    • Linearizability Model for single-operation atomicity.
    • Sequential Consistency Model for program order preservation.
    • Strict Consistency Model for absolute time ordering.
    • Serializability Model for transaction isolation.
  • Weak Consistency Models, such as:
    • Eventual Consistency Model for convergent state.
    • Causal Consistency Model for causality preservation.
    • Read-Your-Writes Consistency Model for session guarantee.
    • Monotonic Read Consistency Model for read progression.
  • Hybrid Consistency Models, such as:
    • Bounded Staleness Model for time-bounded divergence.
    • Consistent Prefix Model for ordered snapshot.
    • Fork Consistency Model for Byzantine fault tolerance.
  • Probabilistic Consistency Models, such as:
    • PBS Consistency Model for probabilistic bound.
    • Calibrated Consistency Model for tunable guarantee.
  • Application-Specific Consistency Models, such as:
    • Session Consistency Model for web applications.
    • Timeline Consistency Model for social media systems.
    • Geo-Replicated Consistency Model for global distribution.
  • ...
• Counter-Examples:
  • Performance Model, which focuses on execution speed.
  • Security Model, which ensures access control.
  • Cost Model, which optimizes resource usage.
• See: Distributed Computational Process, Computational Execution Topology, CAP Theorem, ACID Property, BASE Property, Distributed Database System, Replication Protocol, Consensus Algorithm.

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