rocketmq/docs/en/Configuration_Client.md

Client Configuration

Relative to RocketMQ's Broker cluster, producers and consumers are clients. This section describes the common behavior configuration of producers and consumers, including updates for RocketMQ 5.x.

1 Client Addressing Mode

RocketMQ allows clients to locate the Name Server, which then helps them find the Broker. Below are various configurations, prioritized from highest to lowest. Higher priority configurations override lower ones.

• Specified Name Server address in the code (multiple addresses separated by semicolons):

producer.setNamesrvAddr("192.168.0.1:9876;192.168.0.2:9876");  
consumer.setNamesrvAddr("192.168.0.1:9876;192.168.0.2:9876");

• Specified Name Server address in Java setup parameters:

-Drocketmq.namesrv.addr=192.168.0.1:9876;192.168.0.2:9876  

• Specified Name Server address in environment variables:

export NAMESRV_ADDR=192.168.0.1:9876;192.168.0.2:9876   

• HTTP static server addressing (default):

Clients retrieve Name Server addresses from a static HTTP server:

http://jmenv.tbsite.net:8080/rocketmq/nsaddr

• New in RocketMQ 5.x:

  • Improved service discovery mechanism, allowing dynamic Name Server registration.
  • Introduces VIP_CHANNEL_ENABLED for better failover:

  producer.setVipChannelEnabled(false);
  consumer.setVipChannelEnabled(false);
  

2 Client Configuration

DefaultMQProducer, TransactionMQProducer, DefaultMQPushConsumer, and DefaultMQPullConsumer all extend the ClientConfig class, which provides common client configurations.

2.1 Client Common Configuration

Parameter Name	Default Value	Description
namesrvAddr		Name Server address list (semicolon-separated)
clientIP	Local IP	Client's local IP address (useful if automatic detection fails)
instanceName	DEFAULT	Unique name for the client instance
clientCallbackExecutorThreads	4	Number of communication layer asynchronous callback threads
pollNameServerInterval	30000	Interval (ms) to poll Name Server
heartbeatBrokerInterval	30000	Interval (ms) for sending heartbeats to Broker
persistConsumerOffsetInterval	5000	Interval (ms) for persisting consumer offsets
autoUpdateNameServer (5.x)	true	Automatically update Name Server addresses from registry
instanceId (5.x)		Unique identifier for each client instance

2.2 Producer Configuration

Parameter Name	Default Value	Description
producerGroup	DEFAULT_PRODUCER	Producer group name
sendMsgTimeout	3000	Timeout (ms) for sending messages
retryTimesWhenSendFailed	2	Max retries for failed messages
enableBatchSend (5.x)	true	Enables batch message sending
enableBackPressure (5.x)	true	Prevents overload in high-traffic scenarios

2.3 PushConsumer Configuration

Parameter Name	Default Value	Description
consumerGroup	DEFAULT_CONSUMER	Consumer group name
messageModel	CLUSTERING	Message consumption mode (CLUSTERING or BROADCAST)
consumeFromWhere	CONSUME_FROM_LAST_OFFSET	Default consumption position
consumeThreadMin	20	Min consumption thread count
consumeThreadMax	20	Max consumption thread count
Rebalance Strategies (5.x)	AllocateMessageQueueAveragelyByCircle	New rebalance strategy for better distribution

2.4 PullConsumer Configuration

Parameter Name	Default Value	Description
consumerGroup	DEFAULT_CONSUMER	Consumer group name
brokerSuspendMaxTimeMillis	20000	Max suspension time (ms) for long polling
consumerPullTimeoutMillis	10000	Timeout (ms) for pull requests
messageGroup (5.x)		Enables orderly consumption based on groups

2.5 Message Data Structure

Field Name	Default Value	Description
Topic	null	Required: Name of the message topic
Body	null	Required: Message content
Tags	null	Optional: Tag for filtering
Keys	null	Optional: Business keys (e.g., order IDs)
Flag	0	Optional: Custom flag
DelayTimeLevel	0	Optional: Message delay level
WaitStoreMsgOK	TRUE	Optional: Acknowledgment before storing
maxReconsumeTimes (5.x)		Max retries before moving to dead-letter queue
messageGroup (5.x)		Group-based message ordering

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