1. is it correctly the idea about B ? i think it maybe the major factor
for rebalance in my case ,because consuming data is slowly.
=> Looks like so, but we cannot confirm that because we don't have other
information. You should check the consumer log to see why the consumer
leave group.
2. i have do an experiment for assert B. but not reproduce
A：consumer fast or slow can't trigger it
You should also adjust the heartbeat interval to allow the heartbeat detect
the poll expiration.
You can refer to this test:
https://github.com/apache/kafka/blob/trunk/core/src/test/scala/integration/kafka/api/PlaintextConsumerTest.scala#L167
3. Any tips on APIs or debug techniques to figure out rebalance causes
On server side, you can check log like this:
"Preparing to rebalance group xxx ... (reason: yyyyy)
4. How can I trigger it manually ?
=> same as question 2
5. Is it a bad idea to have the same Consumer Group (Same ID) consuming
from multiple topics ?
=> Depends on your use case, no good or bad.
Thank you.
Luke
On Wed, Apr 27, 2022 at 11:58 PM 杨宝栓 <yangbaosh...@rcrai.com> wrote:
>
>
> HI：
> We are seeing unexpected rebalances in golang consumers, described below.
> 1. We have a topic with 36 partitions，and one consumer (lets name
> it consumer1) consuming it.
> 2. Run kafka in Docker and configuration：We use defaults
> 3. Consumer consuming data is slowly about cost 1s for one
> piece of data
> 4. All the consumers for topic A are in the same group
> 5. The rebalances are intermittent and hard to reproduce. We see
> no obvious errors in the logs.
> 6. No matter how to change the configuration that affects
> rebalance ，it always rebalance
> The configuration that affects rebalance below:
> max.poll.interval.ms
> max.poll.records
> request.timeout.ms
> session.timeout.ms
> As far as I am concerned, conditions of the rebalance contains：
> a consumer is considered DEAD by the group coordinator.
> A. when the consumer is busy, which means that no
> heartbeats has been sent in the meanwhile by the consumer to the group
> coordinator within the configured session interval
> B. when the consumer is slowly with a long-running
> processing, which means that interval of poll() is too long within the
> configured max.poll.interval.ms。
> question：
> 1. is it correctly the idea about B ? i think it maybe the
> major factor for rebalance in my case ,because consuming data is slowly.
> 2. i have do an experiment for assert B. but not reproduce
> A：consumer fast or slow can't trigger it
> 3. Any tips on APIs or debug techniques to figure out rebalance
> causes
> 4. How can I trigger it manually ?
> 5. Is it a bad idea to have the same Consumer Group (Same ID)
> consuming from multiple topics ?
>
>
>
>
>
>
