[ZOOKEEPER-3218] zk server reopened，the interval for observer connect to the new leader is too long，then session expired

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.6.0
• Labels: pull-request-available

Environment

win7 32bits

zookeeper 3.4.6、3.4.13

• Assignee: Unassigned
• Reporter: yangoofy
• Created: 17/Dec/18 20:55
• Updated: 18/Jan/19 06:28
• Resolved: 18/Jan/19 02:45

Description

two participants、one observer，zkclient connect to observer。

Then，close the two participants，the zookeeper server cloesed

Ten seconds later，reopen the two participants，and leader selected

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But the observer can't connect to the new leader immediately。Because in lookForLeader, the observer use blockingQueue(recvqueue)  to offer/poll notifications，when the recvqueue is empty，poll from recvqueue will be blocked，and timeout is 200ms，400ms，800ms....60s。

For example，09:59:59 observer poll notification，recvqueue was empty and timeout was 60s；10:00:00 two participants reopened and reselected；10:00:59 observer polled notification，connected to the new leader

But the maxSessionTimeout default to 40s。The session expired

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Please improve it：observer should connect to the new leader as soon as possible

Issue Links

• links to: GitHub Pull Request #747