@Override
protected void realRun() throws SAXException, IOException, OsmTransferException {
try {
progressMonitor.indeterminateSubTask(null);
OsmServerBackreferenceReader reader = new OsmServerBackreferenceReader(child, full);
referrers = reader.parseOsm(progressMonitor.createSubTaskMonitor(1, false));
if (referrers != null) {
final DataSetMerger visitor = new DataSetMerger(getLayer().data, referrers);
visitor.merge();
// copy the merged layer's data source info