Elementary school with CAP

• History

• Definition

  • Consistency

  • Availability

  • Partition tolerance

• Use case

• Limitations

  • Not choose two from three

  • Limited model

    • Consistency model

    • Fault tolerant model

• References

History

• Applications don't require linearizability can be more tolerant of network problems (CAP)

Definition

Consistency

• Every read would get the most recent write. Actually means linearizability.

Availability

• Availability: Every request received by the nonfailing node in the system must result in a response.

Partition tolerance

• Partition tolerance: The cluster can survive communication breakages in the cluster that separate the cluster into multiple partitions unable to communicate with each other.

Use case

• Simplified theory for elementary distributed system learners.

Limitations

Not choose two from three

• Def: Either choose consistency or availability when partitioned.

Limited model

Consistency model

• It only considers one consistency model (namely linearizability)

Fault tolerant model

• It only considers one kind of fault (network partitions). It doesn't say anything about network delays, dead nodes, or other trade-offs.

References

• https://martin.kleppmann.com/2015/05/11/please-stop-calling-databases-cp-or-ap.html