Consider small periodic impulses as bounded.

robertwb · robertwb · commit 9cc1da4b2322 · 2025-04-28T14:43:52.000-07:00
diff --git a/sdks/python/apache_beam/transforms/combiners_test.py b/sdks/python/apache_beam/transforms/combiners_test.py
@@ -991,6 +991,7 @@ def test_combine_globally_for_unbounded_source_with_default(self):
                 stop_timestamp=time.time() + 4,
                 fire_interval=1,
                 apply_windowing=False,
+                is_bounded=False,
             )
             | beam.Map(lambda x: ('c', 1))
             | beam.WindowInto(
diff --git a/sdks/python/apache_beam/transforms/periodicsequence.py b/sdks/python/apache_beam/transforms/periodicsequence.py
@@ -178,25 +178,35 @@ def __init__(
       start_timestamp=Timestamp.now(),
       stop_timestamp=MAX_TIMESTAMP,
       fire_interval=360.0,
-      apply_windowing=False):
+      apply_windowing=False,
+      is_bounded=None):
     '''
     :param start_timestamp: Timestamp for first element.
     :param stop_timestamp: Timestamp after which no elements will be output.
     :param fire_interval: Interval in seconds at which to output elements.
     :param apply_windowing: Whether each element should be assigned to
       individual window. If false, all elements will reside in global window.
+    :param is_bounded: whether to treat the output PCollection as bounded.
+      Defaults to True for small timestamp ranges and False for large ones.
     '''
     self.start_ts = start_timestamp
     self.stop_ts = stop_timestamp
     self.interval = fire_interval
     self.apply_windowing = apply_windowing
+    self.is_bounded = (
+        stop_timestamp - start_timestamp < 60
+        if is_bounded is None else is_bounded)
 
   def expand(self, pbegin):
-    result = (
+    sequence = (
         pbegin
         | 'ImpulseElement' >> beam.Create(
             [(self.start_ts, self.stop_ts, self.interval)])
-        | 'GenSequence' >> beam.ParDo(ImpulseSeqGenDoFn())
+        | 'GenSequence' >> beam.ParDo(ImpulseSeqGenDoFn()))
+    if self.is_bounded:
+      sequence.is_bounded = True
+    result = (
+        sequence
         | 'MapToTimestamped' >> beam.Map(lambda tt: TimestampedValue(tt, tt)))
     if self.apply_windowing:
       result = result | 'ApplyWindowing' >> beam.WindowInto(
diff --git a/sdks/python/apache_beam/transforms/periodicsequence_test.py b/sdks/python/apache_beam/transforms/periodicsequence_test.py
@@ -91,7 +91,8 @@ def test_periodicimpulse_default_start(self):
     assert is_same_type, error
 
     with TestPipeline() as p:
-      result = p | 'PeriodicImpulse' >> PeriodicImpulse(it, et, interval)
+      result = p | 'PeriodicImpulse' >> PeriodicImpulse(
+          it, et, interval, is_bounded=False)
 
       k = [it + x * interval for x in range(0, int(duration / interval))]
       self.assertEqual(result.is_bounded, False)

Original file line number	Diff line number	Diff line change
`@@ -991,6 +991,7 @@ def test_combine_globally_for_unbounded_source_with_default(self):`
`991`	`991`	`stop_timestamp=time.time() + 4,`
`992`	`992`	`fire_interval=1,`
`993`	`993`	`apply_windowing=False,`
	`994`	`+ is_bounded=False,`
`994`	`995`	`)`
`995`	`996`	`\| beam.Map(lambda x: ('c', 1))`
`996`	`997`	`\| beam.WindowInto(`