Robert Hastings created STORM-1674: -------------------------------------- Summary: Idle KafkaSpout consumes more bandwidth than needed Key: STORM-1674 URL: https://issues.apache.org/jira/browse/STORM-1674 Project: Apache Storm Issue Type: Bug Components: storm-kafka Affects Versions: 0.9.3 Reporter: Robert Hastings
Discovered 30 megabits of traffic flowing between a set of KafkaSpouts and our kafka servers even though no Kafka messages were moving. Using the wireshark kafka dissector, we were able to see that each FetchRequest had maxWait set to 10000 and minBytes set to 0. When binBytes is set to 0 the kafka server responds immediately when there are no messages. In turn the KafkaSpout polls without any delay causing a constant stream of FetchRequest/ FetchResponse messages. Using a non-KafkaSpout client had a similar traffic pattern with two key differences 1) minBytes was 1 2) maxWait was 100 With these FetchRequest parameters and no messages flowing, the kafka server delays the FetchResponse by 100 ms. This reduces the network traffic from megabits to the low kilobits. It also reduced the CPU utilization of our kafka server from 140% to 2%. -- This message was sent by Atlassian JIRA (v6.3.4#6332)