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https://issues.apache.org/jira/browse/HBASE-5549?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13439992#comment-13439992
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Himanshu Vashishtha commented on HBASE-5549:
--------------------------------------------
@Stack: The patch is at HBase-6354. It is based on the approach as mentioned in
the above comment. It works as per current approach, but when I tried to catch
explicitly the "Expired" event in the process method of the watcher, it hangs
as if it never received that event. In that case, the only event it received is
SynConnected, which is when you create a new zk instance.
Basically, this:
{code}
ZooKeeper monitorWatcher = new ZooKeeper(quorumServers, 1000,
new Watcher() {
@Override
public void process(WatchedEvent event) {
KeeperState state = event.getState();
switch (state) {
case Expired:
LOG.info("processing SessionExpired event");
sessionClosed.set(true);
synchronized (sessionClosed) {
sessionClosed.notifyAll();
}
break;
default:
LOG.info("processing default event" +state);
}
}
}, sessionID, password);
{code}
Sorry for the late reply.
> Master can fail if ZooKeeper session expires
> --------------------------------------------
>
> Key: HBASE-5549
> URL: https://issues.apache.org/jira/browse/HBASE-5549
> Project: HBase
> Issue Type: Bug
> Components: master, zookeeper
> Affects Versions: 0.96.0
> Environment: all
> Reporter: nkeywal
> Assignee: nkeywal
> Priority: Minor
> Fix For: 0.96.0
>
> Attachments: 5549_092.txt, 5549.v10.patch, 5549.v11.patch,
> 5549.v6.patch, 5549.v7.patch, 5549.v8.patch, 5549.v9.patch, nochange.patch
>
>
> There is a retry mechanism in RecoverableZooKeeper, but when the session
> expires, the whole ZooKeeperWatcher is recreated, hence the retry mechanism
> does not work in this case. This is why a sleep is needed in
> TestZooKeeper#testMasterSessionExpired: we need to wait for ZooKeeperWatcher
> to be recreated before using the connection.
> This can happen in real life, it can happen when:
> - master & zookeeper starts
> - zookeeper connection is cut
> - master enters the retry loop
> - in the meantime the session expires
> - the network comes back, the session is recreated
> - the retries continues, but on the wrong object, hence fails.
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