跟踪kafka配置max.poll.records参数有否生效

kafka消费客户端使用Spring-kafka第三方库的开源jar包，引入Maven

        
            org.apache.kafka
            kafka_2.10
            0.10.2.1
        
        
            org.springframework.kafka
            spring-kafka
            1.2.1.RELEASE
        
        
            org.apache.kafka
            kafka-clients
            0.10.2.1
        

配置kafka参数max.poll.records 为10

断点调试org.springframework.kafka.listener.KafkaMessageListenerContainer里的run()函数里的以下代码

		long lastReceive = System.currentTimeMillis();
			long lastAlertAt = lastReceive;
			while (isRunning()) {
				try {
					if (!this.autoCommit) {
						processCommits();
					}
					processSeeks();
					if (this.logger.isTraceEnabled()) {
						this.logger.trace("Polling (paused=" + this.paused + ")...");
					}
					ConsumerRecords records = this.consumer.poll(this.containerProperties.getPollTimeout()); //拉取数据在这行代码
					if (records != null && this.logger.isDebugEnabled()) {
						this.logger.debug("Received: " + records.count() + " records");
					}
					if (records != null && records.count() > 0) {
						if (this.containerProperties.getIdleEventInterval() != null) {
							lastReceive = System.currentTimeMillis();
						}
						// if the container is set to auto-commit, then execute in the
						// same thread
						// otherwise send to the buffering queue
						if (this.autoCommit) {
							invokeListener(records);
						}
						else {
							if (sendToListener(records)) {
								if (this.assignedPartitions != null) {
									// avoid group management rebalance due to a slow
									// consumer
									this.consumer.pause(this.assignedPartitions);
									this.paused = true;
									this.unsent = records;
								}
							}
						}
					}
					else {
						if (this.containerProperties.getIdleEventInterval() != null) {
							long now = System.currentTimeMillis();
							if (now > lastReceive + this.containerProperties.getIdleEventInterval()
									&& now > lastAlertAt + this.containerProperties.getIdleEventInterval()) {
								publishIdleContainerEvent(now - lastReceive);
								lastAlertAt = now;
								if (this.theListener instanceof ConsumerSeekAware) {
									seekPartitions(getAssignedPartitions(), true);
								}
							}
						}
					}
					this.unsent = checkPause(this.unsent);
				}
				catch (WakeupException e) {
					this.unsent = checkPause(this.unsent);
				}
				catch (Exception e) {
					if (this.containerProperties.getGenericErrorHandler() != null) {
						this.containerProperties.getGenericErrorHandler().handle(e, null);
					}
					else {
						this.logger.error("Container exception", e);
					}
				}
			}

消费者拉取Kafka broker数据在ConsumerRecords records = this.consumer.poll(this.containerProperties.getPollTimeout()); 这行代码

注意：kafka在0.9版本无max.poll.records参数，默认拉取记录是500，直到0.10版本才引入该参数，所以在0.9版本配置是无效的。

在ConsumerConfig.java类里有做默认配置拉取默认500

 .define(MAX_POLL_RECORDS_CONFIG,
                                        Type.INT,
                                        500,
                                        atLeast(1),
                                        Importance.MEDIUM,
                                        MAX_POLL_RECORDS_DOC)