@Override public void createCatalog(Catalog cat) throws MetaException {
    rawStore.createCatalog(cat);
    // in case of event based cache update, cache will not be updated for catalog.
    if (!canUseEvents) {
      sharedCache.addCatalogToCache(cat);
    }
  }
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