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Type:
Build Failure
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Resolution: Done
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Priority:
Major - P3
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Affects Version/s: None
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Component/s: None
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Python Drivers
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Name of Failure:
test.test_discovery_and_monitoring.TestPoolBackpressure.test_connection_pool_is_not_cleared
Link to task:
Context of when and why the failure occurred:
Has been failing consistently.
Stack trace:
[2026/06/08 07:48:20.861] FAILURE: AssertionError: 3 != 0 () [2026/06/08 07:48:20.861] self = <test.test_discovery_and_monitoring.TestPoolBackpressure testMethod=test_connection_pool_is_not_cleared> [2026/06/08 07:48:20.861] @client_context.require_version_min(7, 0, 0) [2026/06/08 07:48:20.861] def test_connection_pool_is_not_cleared(self): [2026/06/08 07:48:20.861] listener = CMAPListener() [2026/06/08 07:48:20.861] [2026/06/08 07:48:20.861] # Create a client that listens to CMAP events, with maxConnecting=100. [2026/06/08 07:48:20.861] client = self.rs_or_single_client(maxConnecting=100, event_listeners=[listener]) [2026/06/08 07:48:20.861] [2026/06/08 07:48:20.861] # Enable the ingress rate limiter. [2026/06/08 07:48:20.861] client.admin.command( [2026/06/08 07:48:20.861] "setParameter", 1, ingressConnectionEstablishmentRateLimiterEnabled=True [2026/06/08 07:48:20.861] ) [2026/06/08 07:48:20.861] client.admin.command("setParameter", 1, ingressConnectionEstablishmentRatePerSec=20) [2026/06/08 07:48:20.861] client.admin.command("setParameter", 1, ingressConnectionEstablishmentBurstCapacitySecs=1) [2026/06/08 07:48:20.861] client.admin.command("setParameter", 1, ingressConnectionEstablishmentMaxQueueDepth=1) [2026/06/08 07:48:20.861] [2026/06/08 07:48:20.861] # Disable the ingress rate limiter on teardown. [2026/06/08 07:48:20.861] # Sleep for 1 second before disabling to avoid the rate limiter. [2026/06/08 07:48:20.861] def teardown(): [2026/06/08 07:48:20.861] time.sleep(1) [2026/06/08 07:48:20.861] client.admin.command( [2026/06/08 07:48:20.861] "setParameter", 1, ingressConnectionEstablishmentRateLimiterEnabled=False [2026/06/08 07:48:20.861] ) [2026/06/08 07:48:20.861] [2026/06/08 07:48:20.861] self.addCleanup(teardown) [2026/06/08 07:48:20.861] [2026/06/08 07:48:20.861] # Make sure the collection has at least one document. [2026/06/08 07:48:20.861] client.test.test.delete_many({}) [2026/06/08 07:48:20.861] client.test.test.insert_one({}) [2026/06/08 07:48:20.861] [2026/06/08 07:48:20.861] # Run a slow operation to tie up the connection. [2026/06/08 07:48:20.861] def target(): [2026/06/08 07:48:20.861] try: [2026/06/08 07:48:20.861] client.test.test.find_one({"$where": delay(0.1)}) [2026/06/08 07:48:20.861] except ConnectionFailure: [2026/06/08 07:48:20.861] pass [2026/06/08 07:48:20.861] [2026/06/08 07:48:20.861] # Run 100 parallel operations that contend for connections. [2026/06/08 07:48:20.861] tasks = [] [2026/06/08 07:48:20.861] for _ in range(100): [2026/06/08 07:48:20.861] tasks.append(ConcurrentRunner(target=target)) [2026/06/08 07:48:20.861] for t in tasks: [2026/06/08 07:48:20.861] t.start() [2026/06/08 07:48:20.861] for t in tasks: [2026/06/08 07:48:20.861] t.join() [2026/06/08 07:48:20.861] [2026/06/08 07:48:20.861] # Verify there were at least 10 connection checkout failed event but no pool cleared events. [2026/06/08 07:48:20.861] self.assertGreater(len(listener.events_by_type(ConnectionCheckOutFailedEvent)), 10) [2026/06/08 07:48:20.861] > self.assertEqual(len(listener.events_by_type(PoolClearedEvent)), 0) [2026/06/08 07:48:20.861] E AssertionError: 3 != 0 [2026/06/08 07:48:20.861] test/test_discovery_and_monitoring.py:498: AssertionError