Patterns of Distributed Systems

Chapter 14

Request Waiting List

Track client requests which require responses after the criteria to respond is met based on responses from other cluster nodes.

Problem

A cluster node needs to communicate with other cluster nodes to replicate data while processing a client request. A response from all other cluster nodes or a Majority Quorum is needed before responding to clients.

Communication to other cluster nodes is done asynchronously. Asynchronous communication allows patterns like Request Pipeline and Request Batch to be used.

So the cluster node receives and processes responses from multiple other cluster nodes asynchronously. It then needs to correlate them to check if the Majority Quorum for a particular client request is reached. ...