[fix][broker] Fix incorrect number of read compacted entries (apache#20978)

Author: coderzc

pulsar-broker/src/main/java/org/apache/pulsar/compaction/CompactedTopicImpl.java

@@ -119,7 +119,7 @@ public void asyncReadEntriesOrWait(ManagedCursor cursor,
                                 return CompletableFuture.completedFuture(null);
                             } else {
                                 long endPoint = Math.min(context.ledger.getLastAddConfirmed(),
-                                                         startPoint + numberOfEntriesToRead);
+                                                         startPoint + (numberOfEntriesToRead - 1));
                                 return readEntries(context.ledger, startPoint, endPoint)
                                     .thenAccept((entries) -> {
                                         Entry lastEntry = entries.get(entries.size() - 1);

pulsar-broker/src/main/java/org/apache/pulsar/compaction/PulsarTopicCompactionService.java

@@ -78,7 +78,7 @@ public CompletableFuture<List<Entry>> readCompactedEntries(@Nonnull Position sta
                         return CompletableFuture.completedFuture(Collections.emptyList());
                     }
                     long endPoint =
-                            Math.min(context.ledger.getLastAddConfirmed(), startPoint + numberOfEntriesToRead);
+                            Math.min(context.ledger.getLastAddConfirmed(), startPoint + (numberOfEntriesToRead - 1));
                     return CompactedTopicImpl.readEntries(context.ledger, startPoint, endPoint);
                 })).whenComplete((result, ex) -> {
                     if (ex == null) {

pulsar-broker/src/test/java/org/apache/pulsar/compaction/CompactionTest.java

@@ -61,6 +61,7 @@
 import org.apache.pulsar.broker.service.Topic;
 import org.apache.pulsar.broker.service.persistent.PersistentTopic;
 import org.apache.pulsar.broker.service.persistent.SystemTopic;
+import org.apache.pulsar.client.admin.LongRunningProcessStatus;
 import org.apache.pulsar.client.api.CompressionType;
 import org.apache.pulsar.client.api.Consumer;
 import org.apache.pulsar.client.api.CryptoKeyReader;
@@ -70,11 +71,14 @@
 import org.apache.pulsar.client.api.MessageRoutingMode;
 import org.apache.pulsar.client.api.Producer;
 import org.apache.pulsar.client.api.ProducerBuilder;
+import org.apache.pulsar.client.api.PulsarClient;
 import org.apache.pulsar.client.api.PulsarClientException;
 import org.apache.pulsar.client.api.Reader;
+import org.apache.pulsar.client.api.Schema;
 import org.apache.pulsar.client.api.SubscriptionInitialPosition;
 import org.apache.pulsar.client.api.SubscriptionType;
 import org.apache.pulsar.client.impl.BatchMessageIdImpl;
+import org.apache.pulsar.client.impl.ConsumerImpl;
 import org.apache.pulsar.client.impl.MessageIdImpl;
 import org.apache.pulsar.common.naming.NamespaceName;
 import org.apache.pulsar.common.naming.TopicName;
@@ -1783,4 +1787,38 @@ public void addFailed(ManagedLedgerException exception, Object ctx) {
                     Assert.assertNotEquals(ledgerId, -1L);
                 });
     }
+
+    @Test(timeOut = 100000)
+    public void testReceiverQueueSize() throws Exception {
+        final String topicName = "persistent://my-property/use/my-ns/testReceiverQueueSize" + UUID.randomUUID();
+        final String subName = "my-sub";
+        final int receiveQueueSize = 1;
+        @Cleanup
+        PulsarClient client = newPulsarClient(lookupUrl.toString(), 100);
+        Producer<String> producer = pulsarClient.newProducer(Schema.STRING)
+                .enableBatching(false).topic(topicName).create();
+
+        for (int i = 0; i < 10; i++) {
+            producer.newMessage().key(String.valueOf(i % 2)).value(String.valueOf(i)).sendAsync();
+        }
+        producer.flush();
+
+        admin.topics().triggerCompaction(topicName);
+
+        Awaitility.await().untilAsserted(() -> {
+            assertEquals(admin.topics().compactionStatus(topicName).status,
+                    LongRunningProcessStatus.Status.SUCCESS);
+        });
+
+        ConsumerImpl<String> consumer = (ConsumerImpl<String>) client.newConsumer(Schema.STRING)
+                .topic(topicName).readCompacted(true).receiverQueueSize(receiveQueueSize).subscriptionName(subName)
+                .subscribe();
+
+        //Give some time to consume
+        Awaitility.await()
+                .untilAsserted(() -> Assert.assertEquals(consumer.getStats().getMsgNumInReceiverQueue().intValue(),
+                        receiveQueueSize));
+        consumer.close();
+        producer.close();
+    }
 }

pulsar-broker/src/test/java/org/apache/pulsar/compaction/TopicCompactionServiceTest.java

@@ -36,19 +36,25 @@
 import org.apache.pulsar.client.impl.MessageImpl;
 import org.apache.pulsar.common.policies.data.ClusterData;
 import org.apache.pulsar.common.policies.data.TenantInfoImpl;
+import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
 
 public class TopicCompactionServiceTest extends CompactorTest {
 
-    @Test
-    public void test() throws PulsarClientException, PulsarAdminException {
+    @BeforeMethod
+    @Override
+    public void setup() throws Exception {
+        super.setup();
         admin.clusters().createCluster("test", ClusterData.builder().serviceUrl(pulsar.getWebServiceAddress()).build());
         TenantInfoImpl tenantInfo = new TenantInfoImpl(Set.of("role1", "role2"), Set.of("test"));
         String defaultTenant = "prop-xyz";
         admin.tenants().createTenant(defaultTenant, tenantInfo);
         String defaultNamespace = defaultTenant + "/ns1";
         admin.namespaces().createNamespace(defaultNamespace, Set.of("test"));
+    }
 
+    @Test
+    public void test() throws PulsarClientException, PulsarAdminException {
         String topic = "persistent://prop-xyz/ns1/my-topic";
 
         PulsarTopicCompactionService service = new PulsarTopicCompactionService(topic, bk, () -> compactor);
@@ -114,5 +120,8 @@ public void test() throws PulsarClientException, PulsarAdminException {
                 assertEquals(data, "B_3");
             }
         });
+
+        List<Entry> entries2 = service.readCompactedEntries(PositionImpl.EARLIEST, 1).join();
+        assertEquals(entries2.size(), 1);
     }
 }