This PR replaces the namespace store dumb hashmap with an LRU cache to bound the maximum number of namespaces loaded into memory while unbounding the number of namespaces allocated on a sqld instance.
Additionally, this enables fully concurrent access to namespaces by removing the global lock on the namespace store.
This PR replaces the namespace store dumb hashmap with an LRU cache to bound the maximum number of namespaces loaded into memory while unbounding the number of namespaces allocated on a sqld instance. Additionally, this enables fully concurrent access to namespaces by removing the global lock on the namespace store.