Brewer’s Theorem

Image created with Midjourney. Image prompt:
Image created with Midjourney. Image prompt: Visualize Brewer's Theorem (CAP Theorem): A triangle with each vertex representing one of the three properties: Consistency, Availability, and Partition tolerance. In the triangle's center, place a figure struggling to hold all three vertices, symbolizing the trade-offs involved in the theorem. Use a minimalistic 2D style with a neutral color palette, adding color to emphasize the triangle and the central figure.

Brewer's Theorem is essentially another name for the CAP Theorem. The CAP Theorem, which stands for Consistency, Availability, and Partition Tolerance, states that it is impossible for a distributed data store to simultaneously provide more than two out of these three guarantees:

  • Consistency: Every read receives the most recent write or an error.
  • Availability: Every request receives a response, without guarantee that it contains the most recent write.
  • Partition Tolerance: The system continues to operate despite an arbitrary number of messages being dropped (or delayed) by the network between nodes.

Eric Brewer conjectured this theorem in a 2000 keynote at the Symposium on Principles of Distributed Computing (PODC), and it was later proven by Seth Gilbert and Nancy Lynch of MIT. Hence, it is also known as Brewer's Theorem.