rocketmq-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jaskey Lam (JIRA)" <>
Subject [jira] [Commented] (ROCKETMQ-67) Consistent Hash allocate strategy support
Date Mon, 29 May 2017 04:46:04 GMT


Jaskey Lam commented on ROCKETMQ-67:

i wonder why this issue is marked as fixed and closed? is the related pr reviewed and merged?

> Consistent Hash allocate strategy support
> -----------------------------------------
>                 Key: ROCKETMQ-67
>                 URL:
>             Project: Apache RocketMQ
>          Issue Type: New Feature
>          Components: rocketmq-client
>            Reporter: Jaskey Lam
>            Assignee: Jaskey Lam
>             Fix For: 4.1.0-incubating
> For now, the average allocate strategy is very sensitive when clients register and unrigister.
> A Consistent Hash allocate strategy option is valueable for the developers who care more
about latency stabilization and messages duplication.
> Intentions: 
> The default AllocateMessageQueueStrategy is averaging strategy which allocate queue to
consumer as evenly as possible. Whenever queues numbers or consumer numbers changed, say a
new consumer starts or an old consumer shutdowns, a rehashing will be triggered then almost
all consumer suffered from this that they will rebalance to drop old queues and get new queues.
> And that will cause
> message latency from producer to consumer increases at the moment when consumer/queue
numbers change, even when they scale up.
> messages will be duplicated significantly since the offset may not be persisted to broker
and that queue is assigned to another consumer to pull messages from.
> This is especially significant when they have tens of consumer instances and scale-up
or deployment is often.
> Consistent Hash strategy to allocate queue is a good choice for these users.

This message was sent by Atlassian JIRA

View raw message