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Posted to dev@zookeeper.apache.org by "JiangJiafu (JIRA)" <ji...@apache.org> on 2017/05/11 02:58:04 UTC
[jira] [Commented] (ZOOKEEPER-2774) Ephemeral znode will not be
removed when sesstion timeout, if the system time of ZooKeeper node changes
unexpectedly.
[ https://issues.apache.org/jira/browse/ZOOKEEPER-2774?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16005821#comment-16005821 ]
JiangJiafu commented on ZOOKEEPER-2774:
---------------------------------------
Is this PB planed to be solved in 3.4.X???
> Ephemeral znode will not be removed when sesstion timeout, if the system time of ZooKeeper node changes unexpectedly.
> ---------------------------------------------------------------------------------------------------------------------
>
> Key: ZOOKEEPER-2774
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2774
> Project: ZooKeeper
> Issue Type: Bug
> Components: server
> Affects Versions: 3.4.8, 3.4.9, 3.4.10
> Environment: Centos6.5
> Reporter: JiangJiafu
>
> 1. Deploy a ZooKeeper cluster with one node.
> 2. Create a Ephemeral znode.
> 3. Change the system time of the ZooKeeper node to a earlier point.
> 4. Disconnect the client with the ZooKeeper server.
> Then the ephemeral znode will exist for a long time even when session timeout.
> I have read the ZooKeeper source code and I find the code int SessionTrackerImpl.java,
> {code:title=SessionTrackerImpl.java|borderStyle=solid}
> @Override
> synchronized public void run() {
> try {
> while (running) {
> currentTime = System.currentTimeMillis();
> if (nextExpirationTime > currentTime) {
> this.wait(nextExpirationTime - currentTime);
> continue;
> }
> SessionSet set;
> set = sessionSets.remove(nextExpirationTime);
> if (set != null) {
> for (SessionImpl s : set.sessions) {
> setSessionClosing(s.sessionId);
> expirer.expire(s);
> }
> }
> nextExpirationTime += expirationInterval;
> }
> } catch (InterruptedException e) {
> handleException(this.getName(), e);
> }
> LOG.info("SessionTrackerImpl exited loop!");
> }
> {code}
> I think it may be better to use System.nanoTime(), not System.currentTimeMillis, because the later can be changed manually or automatically by a NTP client.
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