Hello Tom,
It is indeed a bit weird, I remember someone else have reported similar
issues before. Do you still have the client-side DEBUG logs when this
happens? I'd like to exclude or narrow down the root cause of whether a
reset indeed happens on the consumer, and if yes, it should contains the
following entries:
"
Fetch offset {} is out of range for partition {}, resetting offset ...
Resetting offset for partition {} to offset {}
"
Guozhang
On Thu, Nov 30, 2017 at 6:11 AM, Tom van den Berge <
tom.vandenbe...@gmail.com> wrote:
> I'm using a (java) consumer with default configuration, so auto-commit is
> enabled. The consumer is reading from 5 partitions of a single topic. The
> consumer processes one message at a time (synchronously). Sometimes, large
> numbers of messages are posted to the topic, and the consumer will have to
> work for one or more hours to process all messages. This is not a problem.
>
> Sometimes, if there is a significant lag, I notice that the committed
> offsets that Kafka reports for the consumer, are very strange, or even
> impossible. It goes up and down. I've created a graph for the
> current-offset and log-end-offset for one partition: https://ibb.co/frJ3eb
> .
> The dotted line is the log-end-offset (seems fine), and the solid line is
> the current-offset, as reported by the kafka-consumer-groups.sh tool.
>
> As you can clearly see, the current offset suddenly drops by a few
> thousand, then gradually increases, but shows a number of spikes, until it
> reaches the original value again, then suddenly increases twice by a few
> thousand. Obviously the current offset should never decrease, but also the
> sudden increases are also impossible; the consumer is technically not able
> to process the messages this fast.
>
> The same behaviour is shown for the other partitions of this consumer, and
> also for other consumers of the same topic.
> I'm using Kafka 0.10.0.1 and kafka-client 0.10.0.1.
>
> Does anyone have an idea on what is happening here?
>
> Regards,
> Tom
>
--
-- Guozhang
