case EXTERNAL_VIEW: {
// check if bucketized
BaseDataAccessor<ZNRecord> baseAccessor = new ZkBaseDataAccessor<ZNRecord>(_zkClient);
List<ZNRecord> records = baseAccessor.getChildren(path, null, 0);
for (ZNRecord record : records) {
HelixProperty property = new HelixProperty(record);
String childPath = path + "/" + record.getId();
int bucketSize = property.getBucketSize();
if (bucketSize > 0) {
// subscribe both data-change and child-change on bucketized parent node
// data-change gives a delete-callback which is used to remove watch
subscribeChildChange(childPath, context);
subscribeDataChange(childPath, context);