My consumer seems to have stopped, why?
First, try to figure out if the consumer has really stopped or is just slow, using our tool
bin/kafka-run-class.sh kafka.tools.ConsumerOffsetChecker --group consumer-group1 --zkconnect zkhost:zkport --topic topic1
Owner = consumer-group1-consumer1
Consumer offset = 70121994703
= 70,121,994,703 (65.31G)
Log size = 70122018287
= 70,122,018,287 (65.31G)
Consumer lag = 23584
= 23,584 (0.00G)
If consumer offset is not moving after some time, then consumer is likely to have stopped. If consumer offset is moving, but consumer lag (difference between the end of the log and the consumer offset) is increasing, the consumer is slower than the producer. If the consumer is slow, the typical solution is to increase the degree of parallelism in the consumer. This may require increasing the number of partitions of a topic. If a consumer has stopped, one of the typical causes is that the application code that consumes messages somehow died and therefore killed the consumer thread. We recommend using a try/catch clause to log all
Throwable in the consumer logic.