[Broker] Disable memory limit controller for broker client and replication clients (#15723)

- disable memory limit by default for broker client and replication clients
- restore maxPendingMessages and maxPendingMessagesAcrossPartitions when memory limit is
  disabled so that pre-PIP-120 default configuration is restored when limit is disabled

Author: lhotari

pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java

@@ -1374,6 +1374,10 @@ public synchronized PulsarClient getClient() throws PulsarServerException {
         if (this.client == null) {
             try {
                 ClientConfigurationData conf = new ClientConfigurationData();
+
+                // Disable memory limit for broker client
+                conf.setMemoryLimitBytes(0);
+
                 conf.setServiceUrl(this.getConfiguration().isTlsEnabled()
                                 ? this.brokerServiceUrlTls : this.brokerServiceUrl);
                 conf.setTlsAllowInsecureConnection(this.getConfiguration().isTlsAllowInsecureConnection());

pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java

@@ -127,6 +127,7 @@
 import org.apache.pulsar.client.admin.PulsarAdminBuilder;
 import org.apache.pulsar.client.api.ClientBuilder;
 import org.apache.pulsar.client.api.PulsarClient;
+import org.apache.pulsar.client.api.SizeUnit;
 import org.apache.pulsar.client.impl.ClientBuilderImpl;
 import org.apache.pulsar.client.impl.conf.ClientConfigurationData;
 import org.apache.pulsar.common.allocator.PulsarByteBufAllocator;
@@ -1199,6 +1200,10 @@ public PulsarClient getReplicationClient(String cluster, Optional<ClusterData> c
                         .enableTcpNoDelay(false)
                         .connectionsPerBroker(pulsar.getConfiguration().getReplicationConnectionsPerBroker())
                         .statsInterval(0, TimeUnit.SECONDS);
+
+                // Disable memory limit for replication client
+                clientBuilder.memoryLimit(0, SizeUnit.BYTES);
+
                 if (data.getAuthenticationPlugin() != null && data.getAuthenticationParameters() != null) {
                     clientBuilder.authentication(data.getAuthenticationPlugin(), data.getAuthenticationParameters());
                 } else if (pulsar.getConfiguration().isAuthenticationEnabled()) {

pulsar-client/src/main/java/org/apache/pulsar/client/impl/MemoryLimitController.java

@@ -80,4 +80,8 @@ public void releaseMemory(long size) {
     public long currentUsage() {
         return currentUsage.get();
     }
+
+    public boolean isMemoryLimited() {
+        return memoryLimit > 0;
+    }
 }

pulsar-client/src/main/java/org/apache/pulsar/client/impl/PulsarClientImpl.java

@@ -92,6 +92,10 @@ public class PulsarClientImpl implements PulsarClient {
 
     private static final Logger log = LoggerFactory.getLogger(PulsarClientImpl.class);
 
+    // default limits for producers when memory limit controller is disabled
+    private static final int NO_MEMORY_LIMIT_DEFAULT_MAX_PENDING_MESSAGES = 1000;
+    private static final int NO_MEMORY_LIMIT_DEFAULT_MAX_PENDING_MESSAGES_ACROSS_PARTITIONS = 50000;
+
     protected final ClientConfigurationData conf;
     private final boolean createdExecutorProviders;
     private LookupService lookup;
@@ -251,7 +255,14 @@ public ProducerBuilder<byte[]> newProducer() {
 
     @Override
     public <T> ProducerBuilder<T> newProducer(Schema<T> schema) {
-        return new ProducerBuilderImpl<>(this, schema);
+        ProducerBuilderImpl<T> producerBuilder = new ProducerBuilderImpl<>(this, schema);
+        if (!memoryLimitController.isMemoryLimited()) {
+            // set default limits for producers when memory limit controller is disabled
+            producerBuilder.maxPendingMessages(NO_MEMORY_LIMIT_DEFAULT_MAX_PENDING_MESSAGES);
+            producerBuilder.maxPendingMessagesAcrossPartitions(
+                    NO_MEMORY_LIMIT_DEFAULT_MAX_PENDING_MESSAGES_ACROSS_PARTITIONS);
+        }
+        return producerBuilder;
     }
 
     @Override