QuotaSnapshotStore<String> getNamespaceSnapshotStore() {
    return namespaceSnapshotStore;
  }
Computes the set of all tables that have quotas defined. This includes tables with quotas
explicitly set on them, in addition to tables that exist namespaces which have a quota defined.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/QuotaObserverChore.java