dont lose your real-time data to stale caches. Lets look at some ways to keep things fresh.

hey everyone, im wrestling with cache invalidation for a system that needs pretty near real-time data. were using Redis as our cache, and while we have strategies for general reads, keeping the cache fresh when underlying data changes rapidly is proving tricky. weve considered time-based expiration, but its not ideal for critical updates. pub/sub seems promising but adds complexity. what are your go-to methods or patterns for handling cache invalidation when data freshness is paramount? any war stories or clever solutions out there?