Update lineage query function.

sdks/python/apache_beam/metrics/cells.py

@@ -811,6 +811,9 @@ def contains(self, value):
     else:
       return False
 
+  def flattened(self):
+    return self.as_trie().flattened()
+
   def to_proto(self) -> metrics_pb2.BoundedTrie:
     return metrics_pb2.BoundedTrie(
         bound=self._bound,

sdks/python/apache_beam/metrics/metric.py

@@ -456,14 +456,18 @@ def add_raw(self, *rollup_segments: str) -> None:
     self.metric.add(rollup_segments)
 
   @staticmethod
-  def query(results: MetricResults, label: str) -> Set[str]:
+  def query(results: MetricResults,
+            label: str,
+            truncated_marker='*') -> Set[str]:
     if not label in Lineage._METRICS:
       raise ValueError("Label {} does not exist for Lineage", label)
     response = results.query(
         MetricsFilter().with_namespace(Lineage.LINEAGE_NAMESPACE).with_name(
-            label))[MetricResults.STRINGSETS]
+            label))[MetricResults.BOUNDED_TRIES]
     result = set()
     for metric in response:
-      result.update(metric.committed)
-      result.update(metric.attempted)
+      for fqn in metric.committed.flattened():
+        result.add(''.join(fqn[:-1]) + (truncated_marker if fqn[-1] else ''))
+      for fqn in metric.attempted.flattened():
+        result.add(''.join(fqn[:-1]) + (truncated_marker if fqn[-1] else ''))
     return result