More details on how the Redis cache is utilized?

[Falco]

@griegm

Does being logged-in/logged-out impact cache hit rates? For reference, the load test mentioned above was using an admin API key.

This is the main thing here. The most aggressive cache happens for anonymous requests, so I’d suggest retrying the load test with some anon robots.

@griegm

Is there an “easy” way for me to search the codebase for which bits of data are cached in Redis

There are a handful of grepable methods, like Discourse.cache.fetch and DistributedCache.new.

@griegm

Are frequently queried/fairly static data such as post contents cached in Redis? Or is Redis primarily used for job scheduling and background processing with Sidekiq and whatnot?

We do cache some infrequent config blobs, but the approach to topics is mostly caching the whole response for the anons, allowing the app to craft a response while barely touching the DB.

Redis is heavily used for Sidekiq and MessageBus.