public int getCachedDatabaseCount() {
    try {
      cacheLock.readLock().lock();
      return databaseCache.size();
    } finally {
      cacheLock.readLock().unlock();
    }
  }
Replaces the old db object with the new one. This will add the new database to cache if it does
not exist.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/cache/SharedCache.java