[ROCKETMQ-184] It takes too long(3-33 seconds) to switch to read from slave when master crashes

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Later
• Fix Version/s: 4.2.0
• Component/s: rocketmq-client, rocketmq-remoting
• Assignee: Xiaorui Wang
• Reporter: Jaskey Lam
• Created: 19/Apr/17 08:32
• Updated: 13/Dec/17 12:34
• Resolved: 13/Dec/17 12:34

Description

When master crashes, no notifier callback is triggered to pull message again.

Instead, it relies on the scan service to trigger timeout and then re pull.

But the pulling command has 30 seconds timeout, and after timeout, pulling operation will be scheduled after 3 seconds.

So it takes 3 to 33 seconds to switch to slave, which is too long and can be optimized.

The root cause is the below repull cost too long to be triggered when master crashes

            @Override
            public void onException(Throwable e) {
                if (!pullRequest.getMessageQueue().getTopic().startsWith(MixAll.RETRY_GROUP_TOPIC_PREFIX)) {
                    log.warn("execute the pull request exception", e);
                }

                DefaultMQPushConsumerImpl.this.executePullRequestLater(pullRequest, PULL_TIME_DELAY_MILLS_WHEN_EXCEPTION);
            }

Issue Links

• links to: GitHub Pull Request #95
• links to: GitHub Pull Request #95