code: public void notifyOfCatalogUpdate() {
          m_procedureInfo = getProcedureInformationfoSupplier();
          m_registeredStatsSources.put(StatsSelector.PROCEDURE,
                  new NonBlockingHashMap<Long, NonBlockingHashSet<StatsSource>>());
      }
docs: Please be noted that this function will be called from Site thread, where
  most other functions in the class are from StatsAgent thread.
  
  Need to release references to catalog related stats sources
  to avoid hoarding references to the catalog.