public PostgresOffset getHighWatermark() {
            return highWatermark;
        }
A {@link FetchTask} implementation for Postgres to read snapshot split.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/postgres-cdc/src/main/java/org/apache/inlong/sort/cdc/postgres/source/fetch/PostgresScanFetchTask.java