@Override
  public void emitRecord(
      MixedFormatRecordWithOffset<T> element,
      SourceOutput<T> sourceOutput,
      MixedFormatSplitState split)
      throws Exception {
    T record = element.record();
    if (!populateRowTime) {
      sourceOutput.collect(record);
    } else {
      Preconditions.checkArgument(
          record instanceof RowData,
          "Custom watermark strategy doesn't support %s, except RowData for now.",
          record.getClass());
      RowData rowData =
          new JoinedRowData(
              (RowData) record, GenericRowData.of(TimestampData.fromEpochMillis(Long.MIN_VALUE)));
      rowData.setRowKind(((RowData) record).getRowKind());
      sourceOutput.collect((T) rowData);
    }
    split.updateOffset(
        new Object[] {
          element.insertFileOffset(),
          element.insertRecordOffset(),
          element.deleteFileOffset(),
          element.deleteRecordOffset()
        });
  }
It signifies whether the Long.MIN_VALUE need to be set into RowData.
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/read/hybrid/reader/MixedFormatRecordEmitter.java