See the answers inline. On Tue, Aug 2, 2016 at 12:23 AM, sat <sathish.al...@gmail.com> wrote:
> Hi, > > I am new to Kafka. We are planning to use Kafka messaging for our > application. I was playing with Kafka 0.9.0.1 version and i have following > queries. Sorry for asking basic questions. > > > 1) I have instantiated Kafka Consumer and invoked > consumer.poll(Long.MAX_VALUE). Although i have specified timeout as > Long.MAX_VALUE, i observe my consumer to fetch records whenever the > publisher publishes a message to a topic. This makes me wonder whether > Kafka Consumer is push or pull mechanism. Please help us understand the > logic of consumer.poll(timeout). > Fetches the data from the topic, waiting up to the specified wait time *if necessary *for a record to become available. Kafka Consumer by design is pull mechanism. Take a look into Kafka Consumer java docs[1]. It's explained in detail. > 2) What are the pros and cons of poll for long timeout vs short timeout. > > Short Timeout Pros: - On shutdown, if no data available in the topic -- Shutdown will be quick Cons: - Number of network trips will be high > > Thanks and Regards > A.SathishKumar > [1]: https://kafka.apache.org/090/javadoc/index.html?org/apache/kafka/clients/consumer/KafkaConsumer.html -- Kamal
