Re: Doc says when doing re-balance, sort by leader then partition, but the code seems sort only on partition

[Guozhang Wang <wa...@gmail.com>]

Hello Xiang,

I took a look at the PartitionAssignor and I agree with you that the doc is
referring to an older version of the code now. It could be updated.

BTW, this logic is referring the old ZK-dependent consumer behavior, which
has been deprecated and will likely be removed in the future major
releases; so we'd probably just remove this part of the web docs when we do
that.



Guozhang


On Thu, Nov 30, 2017 at 4:31 AM, 李响 <wa...@gmail.com> wrote:

> Dear Kafka community,
>
> In the doc -> https://kafka.apache.org/documentation/#distributionimpl
> 4. sort Pt (so partitions on the same broker are clustered together)
> and
> During rebalancing, we try to assign partitions to consumers in such a way
> that reduces the number of broker nodes each consumer has to connect to
>
> If I get it correctly, it means when sorting the partitions, firstly it is
> sorted by leader. Then among those partitions which have the same leader,
> then it is sorted by partition id in numeric order.
>
> While the code of RangeAssignor of
> https://github.com/apache/kafka/blob/trunk/core/src/
> main/scala/kafka/consumer/PartitionAssignor.scala
> seems tell that it is sorted only on partition, not on leader.
>
> My trial also demonstrated that the code is correct.
>
> Is the doc out of date? Or the doc follows some previous versions of Kafka?
> Or my understanding on code has something wrong?
>
> Please kindly advise, thanks!!
>
>
> --
>
>                                                李响 Xiang Li
>
> 邮件 e-mail      ：waterlx@gmail.com
>



-- 
-- Guozhang