Polaris is actually fairly simple to build. The harder question to answer is "why cache is inconsistent" and how you debug. The second half of the post talks ab

Polaris is actually fairly simple to build. The harder question to answer is "why cache is inconsistent" and how you debug. The second half of the post talks about consistency tracing, which tracks all cache data state mutations. Distributed systems are state machines, with consistency tracing keeping track of all the state transitions, debugging cache inconsistencies in an invalidation-based cache is very actionable and managable based on our experience.