Archive for the 'Technical Deep Dive' Category

How quorum queues deliver locally while still offering ordering guarantees

June 23, 2020 by Jack Vanlightly

The team was recently asked about whether and how quorum queues can offer the same message ordering guarantees as classic queues given that they will deliver messages from a local queue replica (leader or follower) when possible. Mirrored queues always deliver from the master (the leader), so delivering from any queue replica sounds like it could impact those guarantees. 

That is the subject of this post. Be warned, this post is a technical deep dive for the curious and the distributed systems enthusiast. We’ll take a look at how quorum queues can deliver messages from any queue replica, leader or follower, without additional coordination (extra to Raft) but maintaining message ordering guarantees.