@Override public void createDatabase(Database db) throws InvalidObjectException, MetaException {
    if (db.getType() == null) {
      db.setType(DatabaseType.NATIVE);
    }
    rawStore.createDatabase(db);
    // in case of event based cache update, cache will be updated during commit.
    if (!canUseEvents) {
      sharedCache.addDatabaseToCache(db);
    }
  }
This starts a background thread, which initially populates the SharedCache and later
periodically gets updates from the metastore db

@param conf
@param runOnlyOnce
@param shouldRunPrewarm
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/cache/CachedStore.java