Pretty cool: the Reddit team replaced a pure-caching based approach to advertising performance data serving (very inflexible) to a Druid-based OLAP system that could both perform like a cache for pre-aggregations as well as handle analytical queries.
This was interesting for me as I had a conversation last week
where “eliminating legacy caching systems” was flagged to me as the next big data pipeline problem to solve. It’s not a problem I’ve personally dealt with but totally
understand why this is such a big pain point and why products like Druid and Materialize will be critical here.