Offset question

[Francis Dallaire <fr...@ubisoft.com>]

Hi,

I have question regarding the offset in kafka (0.8). I've gone through the documentation and did some tests, but I want to make sure I'm on the right track.


*         Are the offsets guaranteed to be sequential in a partition ?

o   Can it contain holes ?

*         How offsets are distributed amongst partitions ?

o   Unique inside a partition, not inside a topic ?

o   What determines where it starts for each partition ?

If you have a link to some documentation, that could be useful.

Thanks,

Francis

Re: Offset question

[Jay Kreps <ja...@gmail.com>]

Offsets always begin at 0 for each partition and increase sequentially from
there. Offsets aren't unique within a topic. As old data is discarded the
first retained offset will not remain 0. The behavior of what is retained
is controlled by your retention settings.

In trunk there is a feature that allows removing messages from the log (
https://cwiki.apache.org/confluence/display/KAFKA/Log+Compaction). This
would leave holes between offsets for topics where you enabled compaction.

-Jay


On Mon, Oct 7, 2013 at 12:45 PM, Francis Dallaire <
francis.dallaire@ubisoft.com> wrote:

> Hi,
>
> I have question regarding the offset in kafka (0.8). I've gone through the
> documentation and did some tests, but I want to make sure I'm on the right
> track.
>
>
> *         Are the offsets guaranteed to be sequential in a partition ?
>
> o   Can it contain holes ?
>
> *         How offsets are distributed amongst partitions ?
>
> o   Unique inside a partition, not inside a topic ?
>
> o   What determines where it starts for each partition ?
>
> If you have a link to some documentation, that could be useful.
>
> Thanks,
>
> Francis
>