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https://issues.apache.org/jira/browse/HDFS-8213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14516311#comment-14516311
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Masatake Iwasaki commented on HDFS-8213:
----------------------------------------
I agree to use independent config keys for DFSClient in order to make
end-to-end tracing from HBase/Accumulo to HDFS work.
Few comments for 001.
---
In {{SpanReceiverHost#getInstance}}, {{loadSpanReceivers}} is called even if
there is already initialized SRH instance. Is it intentional?
{code}
synchronized (SingletonHolder.INSTANCE.lock) {
if (SingletonHolder.INSTANCE.host == null) {
SingletonHolder.INSTANCE.host = new SpanReceiverHost();
}
SingletonHolder.INSTANCE.host.loadSpanReceivers(conf, configPrefix);
ShutdownHookManager.get().addShutdownHook(new Runnable() {
public void run() {
SingletonHolder.INSTANCE.host.closeReceivers();
}
}, 0);
return SingletonHolder.INSTANCE.host;
{code}
---
We need to fix {{TraceUtils#wrapHadoopConf}} which always assumes that prefix
is "hadoop.htrace.".
{code}
public class TraceUtils {
public static final String HTRACE_CONF_PREFIX = "hadoop.htrace.";
{code}
---
Should we add entry for {{hdfs.client.htrace.spanreceiver.classes}} to
hdfs-default.xml?
> DFSClient should use hdfs.client.htrace HTrace configuration prefix rather
> than hadoop.htrace
> ---------------------------------------------------------------------------------------------
>
> Key: HDFS-8213
> URL: https://issues.apache.org/jira/browse/HDFS-8213
> Project: Hadoop HDFS
> Issue Type: Bug
> Affects Versions: 2.7.0
> Reporter: Billie Rinaldi
> Assignee: Colin Patrick McCabe
> Priority: Critical
> Attachments: HDFS-8213.001.patch
>
>
> DFSClient initializing SpanReceivers is a problem for Accumulo, which manages
> SpanReceivers through its own configuration. This results in the same
> receivers being registered multiple times and spans being delivered more than
> once. The documentation says SpanReceiverHost.getInstance should be issued
> once per process, so there is no expectation that DFSClient should do this.
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