docs: @Override
      protected void populateColumnSchema(ArrayList<VoltTable.ColumnInfo> columns) {
          super.populateColumnSchema(columns);
          columns.add(new ColumnInfo(VoltSystemProcedure.CNAME_SITE_ID, VoltSystemProcedure.CTYPE_ID));
          columns.add(new ColumnInfo("PARTITION_ID",  VoltType.INTEGER));
          columns.add(new ColumnInfo("CACHE1_LEVEL",  VoltType.INTEGER));
          columns.add(new ColumnInfo("CACHE2_LEVEL",  VoltType.INTEGER));
          columns.add(new ColumnInfo("CACHE1_HITS",   VoltType.BIGINT));
          columns.add(new ColumnInfo("CACHE2_HITS",   VoltType.BIGINT));
          columns.add(new ColumnInfo("CACHE_MISSES",  VoltType.BIGINT));
          columns.add(new ColumnInfo("PLAN_TIME_MIN", VoltType.BIGINT));
          columns.add(new ColumnInfo("PLAN_TIME_MAX", VoltType.BIGINT));
          columns.add(new ColumnInfo("PLAN_TIME_AVG", VoltType.BIGINT));
          columns.add(new ColumnInfo("FAILURES",      VoltType.BIGINT));
      }