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https://issues.apache.org/jira/browse/ZOOKEEPER-2447?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15406241#comment-15406241
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Vishal Khandelwal commented on ZOOKEEPER-2447:
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Yeah I also looked into patch. The problem i described in the JIRA and fix in
patch are totally different. The way i would like to solve the problem is
reducing the connectTimeout to a lower Value as compared to
sessionTimeout/quorum size. That is place when I was debugging I found the
delay. I agree with folks that "taddr.isReachable" might not work in every
situation. We observe that in our environment as well. Where server in not
pingable but zookeeper connection can work. I tried to fix by reducing the
connecttiemout to a lower or fixed value.so bad host can be caught quickly and
also it is not removed part of the list. In net iteration it will checked for
conenction again. I would submit the patch tomorrow on this if people agree.
Tried it already on our clusters.
> Zookeeper adds good delay when one of the quorum host is not reachable
> -----------------------------------------------------------------------
>
> Key: ZOOKEEPER-2447
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2447
> Project: ZooKeeper
> Issue Type: Bug
> Affects Versions: 3.4.6, 3.5.0
> Reporter: Vishal Khandelwal
> Assignee: Edward Ribeiro
> Fix For: 3.5.3, 3.6.0
>
> Attachments: ZOOKEEPER-2447-MinConnectTimeoutOnly.patch,
> ZOOKEEPER-2447.3.5.patch, withfix.txt, withoutFix.txt
>
>
> StaticHostProvider --> resolveAndShuffle method adds all of the address which
> are valid in the quorum to the list, shuffles them and sends back to client
> connection class. If after shuffling if first node appear to be the one which
> is not reachable, Clientcnx.SendThread.run will keep on connecting to the
> failure till a timeout and the moves to a different node. This adds up random
> delay in zookeeper connection in case a host is down. Rather we could check
> if host is reachable in StaticHostProvider and ignore isReachable is false.
> Same as we do for UnknownHostException Exception.
> This can tested using following test code by providing a valid host which is
> not reachable. for quick test comment Collections.shuffle(tmpList,
> sourceOfRandomness); in StaticHostProvider.resolveAndShuffle
> {code}
> @Test
> public void test() throws Exception {
> EventsWatcher watcher = new EventsWatcher();
> QuorumUtil qu = new QuorumUtil(1);
> qu.startAll();
>
> ZooKeeper zk =
> new ZooKeeper("<hostnamet:2181," + qu.getConnString(), 180 * 1000,
> watcher);
>
> watcher.waitForConnected(CONNECTION_TIMEOUT * 5);
> Assert.assertTrue("connection Established", watcher.isConnected());
> zk.close();
> }
> {code}
> Following fix can be added to StaticHostProvider.resolveAndShuffle
> {code}
> if(taddr.isReachable(4000 // can be some value)) {
> tmpList.add(new InetSocketAddress(taddr,
> address.getPort()));
> }
> {code}
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