private BinlogOffset determineHighWatermark(BinlogOffset lowWatermark) {
        if (snapshotSplit.isWholeSplit()) {
            LOG.info("for split {}, set highWatermark to lowWatermark {} since"
                    + " it reads the whole table ", snapshotSplit, lowWatermark);
            return lowWatermark;
        } else {
            return currentBinlogOffset(jdbcConnection);
        }
    }
for chunk that equals to the whole table we do not need to normalize
the snapshot data and the binlog data, just set high watermark to low watermark
@return highWatermark
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/mysql-cdc/src/main/java/org/apache/inlong/sort/cdc/mysql/debezium/task/MySqlSnapshotSplitReadTask.java