KAFKA-19960: Close pending tasks on shutdown. #21365

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Merged

mjsax merged 17 commits into apache:trunk from Nikita-Shupletsov:KAFKA-19960

Feb 6, 2026

+375 −12

...gration-tests/src/test/java/org/apache/kafka/streams/integration/KafkaStreamsWrapper.java

-Original file line number
+Diff line change
@@ Expand Up / @@ -48,7 +48,11 @@ public List<StreamThread> streamThreads() { @@
         public void setStreamThreadStateListener(final StreamThread.StateListener listener) {
             if (state == State.CREATED) {
                 for (final StreamThread thread : threads) {
-                    thread.setStateListener(listener);
+                    final StreamThread.StateListener originalListener = thread.getStateListener();
+                    thread.setStateListener((t, newState, oldState) -> {
+                        originalListener.onChange(t, newState, oldState);
+                        listener.onChange(t, newState, oldState);
+                    });
                 }
             } else {
                 throw new IllegalStateException("Can only set StateListener in CREATED state. " +
@@ Expand Down @@

...c/test/java/org/apache/kafka/streams/integration/RebalanceTaskClosureIntegrationTest.java

-Original file line number
+Diff line change
@@ -0,0 +1,244 @@
+    /*
+     * Licensed to the Apache Software Foundation (ASF) under one or more
+     * contributor license agreements. See the NOTICE file distributed with
+     * this work for additional information regarding copyright ownership.
+     * The ASF licenses this file to You under the Apache License, Version 2.0
+     * (the "License"); you may not use this file except in compliance with
+     * the License. You may obtain a copy of the License at
+     *
+     *    http://www.apache.org/licenses/LICENSE-2.0
+     *
+     * Unless required by applicable law or agreed to in writing, software
+     * distributed under the License is distributed on an "AS IS" BASIS,
+     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     * See the License for the specific language governing permissions and
+     * limitations under the License.
+     */
+    package org.apache.kafka.streams.integration;
+    import org.apache.kafka.clients.consumer.ConsumerConfig;
+    import org.apache.kafka.common.serialization.LongSerializer;
+    import org.apache.kafka.common.serialization.Serdes;
+    import org.apache.kafka.common.serialization.StringSerializer;
+    import org.apache.kafka.common.utils.Bytes;
+    import org.apache.kafka.common.utils.MockTime;
+    import org.apache.kafka.streams.CloseOptions;
+    import org.apache.kafka.streams.KafkaStreams;
+    import org.apache.kafka.streams.KeyValue;
+    import org.apache.kafka.streams.StreamsConfig;
+    import org.apache.kafka.streams.TopologyWrapper;
+    import org.apache.kafka.streams.integration.utils.EmbeddedKafkaCluster;
+    import org.apache.kafka.streams.integration.utils.IntegrationTestUtils;
+    import org.apache.kafka.streams.processor.StateStore;
+    import org.apache.kafka.streams.processor.StateStoreContext;
+    import org.apache.kafka.streams.processor.internals.StreamThread;
+    import org.apache.kafka.streams.state.KeyValueStore;
+    import org.apache.kafka.streams.state.StoreBuilder;
+    import org.apache.kafka.streams.state.internals.AbstractStoreBuilder;
+    import org.apache.kafka.streams.state.internals.CacheFlushListener;
+    import org.apache.kafka.streams.state.internals.CachedStateStore;
+    import org.apache.kafka.streams.state.internals.RocksDBStore;
+    import org.apache.kafka.test.MockApiProcessorSupplier;
+    import org.apache.kafka.test.TestUtils;
+    import org.junit.jupiter.api.AfterEach;
+    import org.junit.jupiter.api.BeforeEach;
+    import org.junit.jupiter.api.Test;
+    import org.junit.jupiter.api.TestInfo;
+    import java.io.IOException;
+    import java.time.Duration;
+    import java.util.List;
+    import java.util.Properties;
+    import java.util.concurrent.CountDownLatch;
+    import java.util.concurrent.atomic.AtomicInteger;
+    import static org.apache.kafka.streams.utils.TestUtils.safeUniqueTestName;
+    import static org.junit.jupiter.api.Assertions.assertEquals;
+    public class RebalanceTaskClosureIntegrationTest {
+        private static final int NUM_BROKERS = 1;
+        protected static final String INPUT_TOPIC_NAME = "input-topic";
+        private static final int NUM_PARTITIONS = 3;
+        private final EmbeddedKafkaCluster cluster = new EmbeddedKafkaCluster(NUM_BROKERS);
+        private KafkaStreamsWrapper streams1;
+        private KafkaStreamsWrapper streams2;
+        private String safeTestName;
+        @BeforeEach
+        public void before(final TestInfo testInfo) throws InterruptedException, IOException {
+            cluster.start();
+            cluster.createTopic(INPUT_TOPIC_NAME, NUM_PARTITIONS, 1);
+            safeTestName = safeUniqueTestName(testInfo);
+        }
+        @AfterEach
+        public void after() {
+            cluster.stop();
+            if (streams1 != null) {
+                streams1.close(Duration.ofSeconds(30));
+            }
+            if (streams2 != null) {
+                streams2.close(Duration.ofSeconds(30));
+            }
+        }
+        /**
+         * The conditions that we need to meet:
+         * <p><ul>
+         * <li>There is a task with an open store in {@link org.apache.kafka.streams.processor.internals.TasksRegistry#pendingTasksToInit}</li>
+         * <li>StreamThread gets into PENDING_SHUTDOWN state, so that {@link StreamThread#isStartingRunningOrPartitionAssigned} returns false
+         * before we call {@link StreamThread#checkStateUpdater} that would move the task to the StateUpdater </li>
+         * </ul><p>
+         * If all conditions are met, {@code TaskManager} needs to correctly close the open store during shutdown.
+         * <p>
+         * In order to have a task with an open store in the pending task list we first need to have an active task that gets converted
+         * to a standby one during rebalance(see {@link org.apache.kafka.streams.processor.internals.TaskManager#closeAndRecycleTasks}).
+         * Second, we need to avoid the second rebalance, to avoid that the pending tasks is closed during such a rebalance, ie, before we enter the shutdown phase.
+         * <p>
+         * For that this test:
+         * <p><ul>
+         * <li>starts a KS app and waits for it to fully start</li>
+         * <li>starts another KS app which will trigger reassignment</li>
+         * <li>waits for {@link CachedStateStore#clearCache} to be called(it's called during task recycle) and locks on it</li>
+         * <li>sends a message with wrong types to crash the stream thread (this avoids a second rebalance, and enters shutdown directly)</li>
+         * <li>shutdowns the first KS app</li>
+         * <li>releases the lock</li>
+         * </ul><p>
+         * At this point {@link org.apache.kafka.streams.processor.internals.TaskManager#shutdown} will be called,
+         * and we will have a pending task to init with an open store(because tasks keep their stores open during recycle).
+         * <p>
+         * This test verifies that the open store is closed during shutdown.
+         */
+        @Test
+        public void shouldClosePendingTasksToInitAfterRebalance() throws Exception {
+            final CountDownLatch recycleLatch = new CountDownLatch(1);
+            final CountDownLatch pendingShutdownLatch = new CountDownLatch(1);
+            // Count how many times we initialize and close stores
+            final AtomicInteger initCount = new AtomicInteger();
+            final AtomicInteger closeCount = new AtomicInteger();
+            final StoreBuilder<KeyValueStore<Bytes, byte[]>> storeBuilder = new AbstractStoreBuilder<>("testStateStore", Serdes.Integer(), Serdes.ByteArray(), new MockTime()) {
+                @Override
+                public KeyValueStore<Bytes, byte[]> build() {
+                    return new TestRocksDBStore(name, recycleLatch, pendingShutdownLatch, initCount, closeCount);
+                }
+            };
+            final TopologyWrapper topology = new TopologyWrapper();
+            topology.addSource("ingest", INPUT_TOPIC_NAME);
+            topology.addProcessor("my-processor", new MockApiProcessorSupplier<>(), "ingest");
+            topology.addStateStore(storeBuilder, "my-processor");
+            streams1 = new KafkaStreamsWrapper(topology, props("1"));
+            streams1.setStreamThreadStateListener((t, newState, oldState) -> {
+                if (newState == StreamThread.State.PENDING_SHUTDOWN) {
+                    pendingShutdownLatch.countDown();
+                }
+            });
+            streams1.start();
+            TestUtils.waitForCondition(() -> streams1.state() == KafkaStreams.State.RUNNING, "Streams never reached RUNNING state");
+            streams2 = new KafkaStreamsWrapper(topology, props("2"));
+            streams2.start();
+            TestUtils.waitForCondition(() -> streams2.state() == KafkaStreams.State.RUNNING, "Streams never reached RUNNING state");
+            // starting the second KS app triggered a rebalance. Which in turn will recycle active tasks that need to become standby.
+            // That's exactly what we are waiting for
+            recycleLatch.await();
+            // sending a message with wrong key and value types to trigger a stream thread failure and avoid the second rebalance
+            // note that writing this message does not trigger the crash right away -- the thread is still blocked inside `poll()` waiting for the shutdown latch to unlock to complete the previous, still ongoing rebalance
+            IntegrationTestUtils.produceKeyValuesSynchronously(INPUT_TOPIC_NAME, List.of(new KeyValue<>("key", 1L)),
+                    TestUtils.producerConfig(cluster.bootstrapServers(), StringSerializer.class, LongSerializer.class, new Properties()), cluster.time);
+            // Now we can close both apps. The StreamThreadStateListener will unblock the clearCache call, letting the rebalance finish.
+            // After the rebalance finished, the "poison pill" record gets picked up crashing the thread,
+            // and starting the shutdown directly
+            // We don't want to let the rebalance finish before we trigger the shutdown, because we want the stream thread to stop before it gets to moving pending tasks from task registry to state updater.
+            streams1.close(CloseOptions.groupMembershipOperation(CloseOptions.GroupMembershipOperation.LEAVE_GROUP));
+            streams2.close(CloseOptions.groupMembershipOperation(CloseOptions.GroupMembershipOperation.LEAVE_GROUP));
+            assertEquals(initCount.get(), closeCount.get());
+        }
+        private Properties props(final String storePathSuffix) {
+            final Properties streamsConfiguration = new Properties();
+            streamsConfiguration.put(StreamsConfig.APPLICATION_ID_CONFIG, safeTestName);
+            streamsConfiguration.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, cluster.bootstrapServers());
+            streamsConfiguration.put(ConsumerConfig.DEFAULT_API_TIMEOUT_MS_CONFIG, 1000);
+            streamsConfiguration.put(ConsumerConfig.REQUEST_TIMEOUT_MS_CONFIG, 1000);
+            streamsConfiguration.put(StreamsConfig.STATE_DIR_CONFIG, TestUtils.tempDirectory().getPath() + "/" + storePathSuffix);
+            streamsConfiguration.put(StreamsConfig.STATESTORE_CACHE_MAX_BYTES_CONFIG, 0);
+            streamsConfiguration.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, 100L);
+            streamsConfiguration.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.LongSerde.class);
+            streamsConfiguration.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.StringSerde.class);
+            streamsConfiguration.put(StreamsConfig.NUM_STANDBY_REPLICAS_CONFIG, 1);
+            return streamsConfiguration;
+        }
+        private static class TestRocksDBStore extends RocksDBStore implements CachedStateStore<Bytes, byte[]> {
+            private final CountDownLatch recycleLatch;
+            private final CountDownLatch pendingShutdownLatch;
+            private final AtomicInteger initCount;
+            private final AtomicInteger closeCount;
+            public TestRocksDBStore(final String name,
+                                    final CountDownLatch recycleLatch,
+                                    final CountDownLatch pendingShutdownLatch,
+                                    final AtomicInteger initCount,
+                                    final AtomicInteger closeCount) {
+                super(name, "rocksdb");
+                this.recycleLatch = recycleLatch;
+                this.pendingShutdownLatch = pendingShutdownLatch;
+                this.initCount = initCount;
+                this.closeCount = closeCount;
+            }
+            @Override
+            public void init(final StateStoreContext stateStoreContext,
+                             final StateStore root) {
+                initCount.incrementAndGet();
+                super.init(stateStoreContext, root);
+            }
+            @Override
+            public boolean setFlushListener(final CacheFlushListener<Bytes, byte[]> listener,
+                                            final boolean sendOldValues) {
+                return false;
+            }
+            @Override
+            public void flushCache() {
+            }
+            @Override
+            public void clearCache() {
+                // Clear cache is called during recycle, so we use it as a hook
+                recycleLatch.countDown();
+                try {
+                    // after we signaled via recycleLatch, that the task was converted into a "pending task",
+                    // we block the rebalance to complete, until we get the shutdown signal,
+                    // to avoid that the "pending task" get fully initialized
+                    // (otherwise, we don't have a pending task when the shutdown happens)
+                    pendingShutdownLatch.await();
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+            }
+            @Override
+            public synchronized void close() {
+                closeCount.incrementAndGet();
+                super.close();
+            }
+        }
+    }

streams/src/main/java/org/apache/kafka/streams/processor/internals/TaskManager.java

-Original file line number
+Diff line change
@@ Expand Up / @@ -1414,10 +1414,20 @@ void shutdown(final boolean clean) { @@
             // TODO: change type to `StreamTask`
             final Set<Task> activeTasks = new TreeSet<>(Comparator.comparing(Task::id));
             activeTasks.addAll(tasks.activeTasks());
+            // TODO: change type to `StandbyTask`
+            final Set<Task> standbyTasks = new TreeSet<>(Comparator.comparing(Task::id));
+            standbyTasks.addAll(tasks.standbyTasks());
+            final Set<Task> pendingActiveTasks = tasks.drainPendingActiveTasksToInit();
+            activeTasks.addAll(pendingActiveTasks);
+            tasks.addPendingTasksToClose(pendingActiveTasks);
+            final Set<Task> pendingStandbyTasks = tasks.drainPendingStandbyTasksToInit();
+            standbyTasks.addAll(pendingStandbyTasks);
+            tasks.addPendingTasksToClose(pendingStandbyTasks);
             executeAndMaybeSwallow(
                 clean,
-                () -> closeAndCleanUpTasks(activeTasks, standbyTaskIterable(), clean),
+                () -> closeAndCleanUpTasks(activeTasks, standbyTasks, clean),
                 e -> firstException.compareAndSet(null, e),
                 e -> log.warn("Ignoring an exception while unlocking remaining task directories.", e)
             );
@@ Expand Down Expand Up @@
                                                           final boolean clean,
                                                           final AtomicReference<RuntimeException> firstException) {
             if (!clean) {
-                return activeTaskIterable();
+                return activeTasksToClose;
             }
             final Comparator<Task> byId = Comparator.comparing(Task::id);
             final Set<Task> tasksToCommit = new TreeSet<>(byId);
@@ Expand Down Expand Up @@
                     }
                 }
-                for (final Task task : activeTaskIterable()) {
+                for (final Task task : activeTasksToClose) {
                     try {
                         task.postCommit(true);
                     } catch (final RuntimeException e) {
@@ Expand Down Expand Up @@
                                                            final boolean clean,
                                                            final AtomicReference<RuntimeException> firstException) {
             if (!clean) {
-                return standbyTaskIterable();
+                return standbyTasksToClose;
             }
             final Set<Task> tasksToCloseDirty = new TreeSet<>(Comparator.comparing(Task::id));
@@ Expand Down @@

streams/src/main/java/org/apache/kafka/streams/processor/internals/Tasks.java

-Original file line number
+Diff line change
@@ Expand Up / @@ -58,6 +58,7 @@ class Tasks implements TasksRegistry { @@
         private final Map<TaskId, Set<TopicPartition>> pendingActiveTasksToCreate = new HashMap<>();
         private final Map<TaskId, Set<TopicPartition>> pendingStandbyTasksToCreate = new HashMap<>();
         private final Set<Task> pendingTasksToInit = new HashSet<>();
+        private final Set<Task> pendingTasksToClose = new HashSet<>();
         private final Set<TaskId> failedTaskIds = new HashSet<>();
         // TODO: convert to Stream/StandbyTask when we remove TaskManager#StateMachineTask with mocks
@@ Expand Down Expand Up / @@ -124,6 +125,20 @@ public Set<Task> drainPendingActiveTasksToInit() { @@
             return result;
         }
+        @Override
+        public Set<Task> drainPendingStandbyTasksToInit() {
+            final Set<Task> result = new HashSet<>();
+            final Iterator<Task> iterator = pendingTasksToInit.iterator();
+            while (iterator.hasNext()) {
+                final Task task = iterator.next();
+                if (!task.isActive()) {
+                    result.add(task);
+                    iterator.remove();
+                }
+            }
+            return result;
+        }
         @Override
         public Set<Task> pendingTasksToInit() {
             return Collections.unmodifiableSet(pendingTasksToInit);
@@ Expand All / @@ -139,6 +154,21 @@ public boolean hasPendingTasksToInit() { @@
             return !pendingTasksToInit.isEmpty();
         }
+        @Override
+        public Set<Task> pendingTasksToClose() {
+            return Collections.unmodifiableSet(pendingTasksToClose);
+        }
+        @Override
+        public void addPendingTasksToClose(final Collection<Task> tasks) {
+            pendingTasksToClose.addAll(tasks);
+        }
+        @Override
+        public boolean hasPendingTasksToClose() {
+            return !pendingTasksToClose.isEmpty();
+        }
         @Override
         public void addActiveTasks(final Collection<Task> newTasks) {
             if (!newTasks.isEmpty()) {
@@ Expand Down Expand Up @@
                 throw new IllegalStateException("Attempted to remove a task that is not closed or suspended: " + taskId);
             }
-            if (taskToRemove.isActive()) {
+            if (pendingTasksToClose.contains(taskToRemove)) {
+                pendingTasksToClose.remove(taskToRemove);
+            } else if (taskToRemove.isActive()) {
                 if (activeTasksPerId.remove(taskId) == null) {
                     throw new IllegalArgumentException("Attempted to remove an active task that is not owned: " + taskId);
                 }
@@ Expand All @@
                     throw new IllegalArgumentException("Attempted to remove a standby task that is not owned: " + taskId);
                 }
             }
-            failedTaskIds.remove(taskToRemove.id());
+            failedTaskIds.remove(taskId);
         }
         @Override
@@ Expand Down Expand Up / @@ -301,6 +333,11 @@ public synchronized Collection<Task> activeTasks() { @@
             return Collections.unmodifiableCollection(activeTasksPerId.values());
         }
+        @Override
+        public synchronized Collection<Task> standbyTasks() {
+            return Collections.unmodifiableCollection(standbyTasksPerId.values());
+        }
         /**
          * All tasks returned by any of the getters are read-only and should NOT be modified;
          * and the returned task could be modified by other threads concurrently
@@ Expand Down @@

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KAFKA-19960: Close pending tasks on shutdown. #21365

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