code: boolean incrNumberRuns(List<Cell> column, Table aggTable,
        AppAggregationKey appAggKey) throws IOException {
  
      /*
       * check if this is the very first insert for numbers for this app in that
       * case, there will no existing column/value for number of run in info col
       * family null signifies non existence of the column for {@link
       * Table.checkAndPut}
       */
      long expectedValueBeforePut = 0L;
      if (column.size() > 0) {
        try {
          expectedValueBeforePut = Bytes.toLong(column.get(0).getValue());
        } catch (NumberFormatException e) {
          LOG.error(
              "Could not read existing value for number of runs during aggregation"
                  + appAggKey.toString());
          return false;
        }
      }
  
      byte[] rowKey = aggConv.toBytes(appAggKey);
  
      long insertValue = 1L;
      byte[] expectedValueBeforePutBytes = null;
      if (expectedValueBeforePut != 0L) {
        insertValue = 1 + expectedValueBeforePut;
        expectedValueBeforePutBytes = Bytes.toBytes(expectedValueBeforePut);
      }
      byte[] insertValueBytes = Bytes.toBytes(insertValue);
  
      if (LOG.isTraceEnabled()) {
        LOG.trace(" before statusCheckAndPut " + insertValue + " "
            + expectedValueBeforePut);
      }
      return executeCheckAndPut(aggTable, rowKey, expectedValueBeforePutBytes,
          insertValueBytes, AggregationConstants.INFO_FAM_BYTES,
          AggregationConstants.NUMBER_RUNS_BYTES);
    }
docs: checks and increments the number of runs for this app aggregation. no need
  to retry, since another map task may have updated it in the mean time
  @throws IOException