code: private long getAppendHighWatermark(ExtractType extractType) {
      LOG.debug("Getting append high water mark");
      if (this.isFullDump()) {
        LOG.info("Overriding high water mark with end value:" + ConfigurationKeys.SOURCE_QUERYBASED_END_VALUE);
        long highWatermark = this.state.getPropAsLong(ConfigurationKeys.SOURCE_QUERYBASED_END_VALUE, 0);
        if (highWatermark != 0) {
          // User specifies SOURCE_QUERYBASED_END_VALUE
          hasUserSpecifiedHighWatermark = true;
        }
        return highWatermark;
      }
      return this.getAppendWatermarkCutoff(extractType);
    }
docs: Get append high water mark
  
  @param extractType Extract type
  @return append high water mark