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https://issues.apache.org/jira/browse/HADOOP-17116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17154757#comment-17154757
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Hanisha Koneru commented on HADOOP-17116:
-----------------------------------------
[~ayushtkn], thanks for the UT. Helped me with the debug.
{{ObserverReadProxyProvider}} is using s \{{combinedProxy}} object which
assigns \{{combinedInfo}} as the ProxyInfo.
{noformat}
ObserverReadProxyProvider# Lines 197-207:
for (int i = 0; i < nameNodeProxies.size(); i++) {
if (i > 0) {
combinedInfo.append(",");
}
combinedInfo.append(nameNodeProxies.get(i).proxyInfo);
}
combinedInfo.append(']');
T wrappedProxy = (T) Proxy.newProxyInstance(
ObserverReadInvocationHandler.class.getClassLoader(),
new Class<?>[] {xface}, new ObserverReadInvocationHandler());
combinedProxy = new ProxyInfo<>(wrappedProxy, combinedInfo.toString()){noformat}
RetryInvocationHandler depends on the ProxyInfo to differentiate between
proxies while checking if failover from that proxy happened before.
{code:java}
failedAtLeastOnce.add(proxyDescriptor.getProxyInfo().toString());
{code}
And since combined proxy has only 1 proxy (or assigns the same ProxyInfo to all
proxies), we see the multiple failover messages.
> Skip Retry INFO logging on first failover from a proxy
> ------------------------------------------------------
>
> Key: HADOOP-17116
> URL: https://issues.apache.org/jira/browse/HADOOP-17116
> Project: Hadoop Common
> Issue Type: Bug
> Components: ha
> Reporter: Hanisha Koneru
> Assignee: Hanisha Koneru
> Priority: Major
> Attachments: HADOOP-17116.001.patch, HADOOP-17116.002.patch,
> HADOOP-17116.003.patch
>
>
> RetryInvocationHandler logs an INFO level message on every failover except
> the first. This used to be ideal before when there were only 2 proxies in the
> FailoverProxyProvider. But if there are more than 2 proxies (as is possible
> with 3 or more NNs in HA), then there could be more than one failover to find
> the currently active proxy.
> To avoid creating noise in clients logs/ console, RetryInvocationHandler
> should skip logging once for each proxy.
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