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From Chia-Chun Shih <chiachun.s...@gmail.com>
Subject Re: Consumer reading from same topic twice without commiting
Date Fri, 14 Nov 2014 23:31:52 GMT
Auto Commit is to sync offset to zookeeper periodically. Without auto
commit, consumer still maintains an offset locally. It explains this

To be able to rewind, you need to use SimpleConsumer.
2014/11/15 上午2:18 於 "dinesh kumar" <dinesh12b@gmail.com> 寫道:

> Hi,
> I am trying to understand the behavior of Kafka Consumer in Java.
> Consider a scenario where a consumer is reading from a partition with
> auto.comiit disabled and only one partition in the topic. The consumer
> reads a message 'A' and sleep for some time, say 10 seconds. Then reads
> from the same parition once again from the without commiting the offsets of
>  the previous read a message 'B'.
> My assumption was since there was no commit of the previous offset we will
> get the same message message 'A' and message 'B' should be the same.
> I ran a simple code with this assumption but I was suprised to see message
> 'A' and message 'B' were different (Producer produced Message 'B' after
> message 'A').
> Can someone explain this behavior? Is there a way to make the consumer
> return message 'A' instead of message 'B' without restarting the consumer
> (which will trigger a repartition in a multi partition/ multi consumer
> scenario), say some parameter or a method call to rewind locally?
> Thanks,
> Dinesh

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