[Bug] Java Pulsar Producer - ProducerBuilder loadConf() throws RuntimeException when loading "maxPendingMessages" property from config map.

Search before asking

• I searched in the issues and found nothing similar.

Version

Pulsar version: 2.10.1

Minimal reproduce step

Add maxPendingMessages parameter into the config map and load the config.

                        HashMap<String, Object> pulsarProducerProperties = new HashMap<String, Object>();
                        pulsarProducerProperties.put("topicName", "my-topic");
                        pulsarProducerProperties.put("producerName", "my-producer");
                        pulsarProducerProperties.put("maxPendingMessages", 2000);
			pulsarProducer = pulsarClient.newProducer()
							.loadConf(pulsarProducerProperties)
							.create();

What did you expect to see?

This seems to be a regression because this seems to be working in Pulsar 2.9.2 .

What did you see instead?

A runtime exception is thrown by loadConf() method

Exception: java.lang.RuntimeException: Failed to load config into existing configuration data

If the maxPendingMessages config is removed from the map , the Producer is created but the masPendingMessages value is 0 instead of the default value of1000 as documented.

10:50:06.730 [pulsar-client-io-1-1] INFO  org.apache.pulsar.client.impl.ProducerStatsRecorderImpl - Starting Pulsar producer perf with config: {"topicName":"my-topic","producerName":"my-producer","sendTimeoutMs":30000,"blockIfQueueFull":false,"maxPendingMessages":0,"maxPendingMessagesAcrossPartitions":0,"messageRoutingMode":"RoundRobinPartition","hashingScheme":"JavaStringHash","cryptoFailureAction":"FAIL","batchingMaxPublishDelayMicros":1000,"batchingPartitionSwitchFrequencyByPublishDelay":10,"batchingMaxMessages":1000,"batchingMaxBytes":131072,"batchingEnabled":true,"chunkingEnabled":false,"compressionType":"NONE","initialSequenceId":null,"autoUpdatePartitions":true,"autoUpdatePartitionsIntervalSeconds":60,"multiSchema":true,"accessMode":"Shared","lazyStartPartitionedProducers":false,"properties":{},"initialSubscriptionName":null}

Anything else?

Tried to use the PulsarBuilder API to set the maxPendingMessages and leave some other configuration in the config map (still using loadConfig()) hit the same exception. Code snippet as below (omitted the other producer config set in the config of type HashMap<String,Object>.

			pulsarProducer = pulsarClient.newProducer()
							.topic(topicName)
							.producerName(producerName)
							.maxPendingMessages(2000)
							.loadConf(pulsarProducerProperties)
							.create();

I looked through the codes and couldn’t find exactly what is the root cause of this error. Appreciate any pointers from the community.

Are you willing to submit a PR?

• I’m willing to submit a PR!

[MarvinCai]

We should use memoryLimit instead: https://github.com/apache/pulsar/issues/13306

[tisonkun]

Closed as answered.