code: public UNode getStatistics(ApplicationDefinition appDef, String shard, Map<String, String> paramMap) {
          checkServiceState();
          CubeSearcher searcher = m_olap.getSearcher(appDef, shard);
          String file = paramMap.get("file");
          if(file != null) {
              return OlapStatistics.getFileData(searcher, file);
          }
          String sort = paramMap.get("sort");
          boolean memStats = !"false".equals(paramMap.get("mem"));
          return OlapStatistics.getStatistics(searcher, sort, memStats);
      }
docs: Get detailed shard statistics for the given shard. This command is mostly used for
  development and diagnostics.
  
  @param appDef    {@link ApplicationDefinition} of application to query.
  @param shard     Name of shard to query.
  @param paramMap  Map of statistic option key/value pairs.
  @return          Root of statistics information as a {@link UNode} tree.