"To reduce the GC impact from the storage engine, we considered different approaches and ultimately decided to develop a C++ storage engine to replace existing ones."
Yes, also Azul Zing. Really anytime someone says they have a problem with GC and suggests spending a million dollars of engineer time building a new system, they should consider Zing first. It works and is a way more efficient way of spending money to fix GC latency problems.
Because GC related issues don't undergo from "problem" state to "solved" state. It is just a never ending stream of issues, that the team need to resolve, specially in a database realm in which metrics are hugely workload dependent.