yangoofy created ZOOKEEPER-3218:
-----------------------------------
Summary: zk集群挂掉重启后，observer重新连上leader的时间间隔可能过长，导致客户端session失效
Key: ZOOKEEPER-3218
URL: https://issues.apache.org/jira/browse/ZOOKEEPER-3218
Project: ZooKeeper
Issue Type: Bug
Environment: win7 32bits
zookeeper 3.4.6、3.4.13
Reporter: yangoofy
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
----------------------------------------------------------------------------
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
-----------------------------------------------------------------------------
Please improve it：observer should connect to the new leader as soon as possible
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
