I was just looking this up and it's correct, they don't cache queries (if they do, it's a separate feature), they only manage query planning in ways that make them faster.

Even CochroachDB doesn't do query cache, only query planning is cached. [0] [1]

[0] https://www.cockroachlabs.com/blog/memory-usage-cockroachdb/

[1] https://www.cockroachlabs.com/blog/query-plan-caching-in-coc...