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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. Another possibility is that the fetch size in the consumer is smaller than the largest message in the broker. You can use the DumpLogSegments tool to figure out the largest message size and set fetch.size in the consumer config accordingly.

Brokers

How do I choose the number of partitions for a topic?

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