Hello all, I'm planning on contributing for the first time. I'm working on https://github.com/apache/druid/issues/8399. No issues seem to occur when replacing guava with caffeine in any of the classes posted in the issue with exception of the class, OnHeapLoadingCache.
I wanted to post something here as I believe it will require a config change to use caffeine in this case. ( https://druid.apache.org/docs/latest/development/extensions-core/druid-lookups.html#example-loading-on-heap-guava). It seems as if guava's `concurrencyLevel` is not a property in caffeine's cache. Currently there are types `guava` and `mapDb`. To prevent a config change a third cache type, caffeine, can be added and the guava cache can be marked as deprecated and potentially removed in some future major release. The configs would be identical to the guava type with exception of `concurrencyLevel` (it will be removed for the caffeine option). What do you all think of this? Is there another solution that is preferred? Thanks, JJ