# Motivation (#14895)

Currently, the transaction buffer don't be closed when deleting topic.

# Modification

Close the transaction buffer when deleting topic.

(cherry picked from commit e8d52fd)

pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentTopic.java

@@ -1151,7 +1151,8 @@ private CompletableFuture<Void> delete(boolean failIfHasSubscriptions,
                     deleteTopicAuthenticationFuture.thenCompose(
                                     __ -> deleteSchema ? deleteSchema() : CompletableFuture.completedFuture(null))
                             .thenAccept(__ -> deleteTopicPolicies())
-                            .thenCompose(__ -> transactionBuffer.clearSnapshot()).whenComplete((v, ex) -> {
+                            .thenCompose(__ -> transactionBufferCleanupAndClose())
+                            .whenComplete((v, ex) -> {
                         if (ex != null) {
                             log.error("[{}] Error deleting topic", topic, ex);
                             unfenceTopicToResume();
@@ -3160,6 +3161,10 @@ public CompletableFuture<ManagedLedger> getPendingAckManagedLedger(String subNam
         return subscription.getPendingAckManageLedger();
     }
 
+    private CompletableFuture<Void> transactionBufferCleanupAndClose() {
+        return transactionBuffer.clearSnapshot().thenCompose(__ -> transactionBuffer.closeAsync());
+    }
+
     public long getLastDataMessagePublishedTimestamp() {
         return lastDataMessagePublishedTimestamp;
     }

pulsar-broker/src/test/java/org/apache/pulsar/broker/transaction/buffer/TransactionBufferCloseTest.java

@@ -0,0 +1,120 @@
+/**
+ * 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.pulsar.broker.transaction.buffer;
+
+import com.google.common.collect.Sets;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.RandomStringUtils;
+import org.apache.pulsar.broker.transaction.TransactionTestBase;
+import org.apache.pulsar.client.admin.PulsarAdminException;
+import org.apache.pulsar.client.api.PulsarClientException;
+import org.apache.pulsar.client.api.transaction.TransactionCoordinatorClient;
+import org.apache.pulsar.client.impl.PulsarClientImpl;
+import org.apache.pulsar.common.events.EventsTopicNames;
+import org.apache.pulsar.common.naming.NamespaceName;
+import org.apache.pulsar.common.naming.TopicDomain;
+import org.apache.pulsar.common.naming.TopicName;
+import org.apache.pulsar.common.policies.data.PublisherStats;
+import org.apache.pulsar.common.policies.data.TenantInfoImpl;
+import org.awaitility.Awaitility;
+import org.testng.Assert;
+import org.testng.annotations.AfterMethod;
+import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.DataProvider;
+import org.testng.annotations.Test;
+
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Transaction buffer close test.
+ */
+@Slf4j
+@Test(groups = "broker")
+public class TransactionBufferCloseTest extends TransactionTestBase {
+
+    @BeforeMethod
+    protected void setup() throws Exception {
+        setUpBase(1, 16, null, 0);
+        Awaitility.await().until(() -> ((PulsarClientImpl) pulsarClient)
+                .getTcClient().getState() == TransactionCoordinatorClient.State.READY);
+        admin.tenants().createTenant(TENANT,
+                new TenantInfoImpl(Sets.newHashSet("appid1"), Sets.newHashSet(CLUSTER_NAME)));
+    }
+
+    @AfterMethod(alwaysRun = true)
+    protected void cleanup() throws Exception {
+        super.internalCleanup();
+    }
+
+    @DataProvider(name = "isPartition")
+    public Object[][] isPartition() {
+        return new Object[][]{
+                { true }, { false }
+        };
+    }
+
+    @Test(timeOut = 10_000, dataProvider = "isPartition")
+    public void deleteTopicCloseTransactionBufferTest(boolean isPartition) throws Exception {
+        int expectedCount = isPartition ? 30 : 1;
+        TopicName topicName = createAndLoadTopic(isPartition, expectedCount);
+        checkSnapshotPublisherCount(topicName.getNamespace(), expectedCount);
+        if (isPartition) {
+            admin.topics().deletePartitionedTopic(topicName.getPartitionedTopicName(), true);
+        } else {
+            admin.topics().delete(topicName.getPartitionedTopicName(), true);
+        }
+        checkSnapshotPublisherCount(topicName.getNamespace(), 0);
+    }
+
+    @Test(timeOut = 10_000, dataProvider = "isPartition")
+    public void unloadTopicCloseTransactionBufferTest(boolean isPartition) throws Exception {
+        int expectedCount = isPartition ? 30 : 1;
+        TopicName topicName = createAndLoadTopic(isPartition, expectedCount);
+        checkSnapshotPublisherCount(topicName.getNamespace(), expectedCount);
+        admin.topics().unload(topicName.getPartitionedTopicName());
+        checkSnapshotPublisherCount(topicName.getNamespace(), 0);
+    }
+
+    private TopicName createAndLoadTopic(boolean isPartition, int partitionCount)
+            throws PulsarAdminException, PulsarClientException {
+        String namespace = TENANT + "/ns-" + RandomStringUtils.randomAlphabetic(5);
+        admin.namespaces().createNamespace(namespace, 3);
+        String topic = namespace + "/tb-close-test-";
+        if (isPartition) {
+            admin.topics().createPartitionedTopic(topic, partitionCount);
+        }
+        pulsarClient.newProducer()
+                .topic(topic)
+                .sendTimeout(0, TimeUnit.SECONDS)
+                .create()
+                .close();
+        return TopicName.get(topic);
+    }
+
+    private void checkSnapshotPublisherCount(String namespace, int expectCount) throws PulsarAdminException {
+        TopicName snTopicName = TopicName.get(TopicDomain.persistent.value(), NamespaceName.get(namespace),
+                EventsTopicNames.TRANSACTION_BUFFER_SNAPSHOT);
+        List<PublisherStats> publisherStatsList =
+                (List<PublisherStats>) admin.topics()
+                        .getStats(snTopicName.getPartitionedTopicName()).getPublishers();
+        Assert.assertEquals(publisherStatsList.size(), expectCount);
+    }
+
+}