[
https://issues.apache.org/jira/browse/HTRACE-275?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14967671#comment-14967671
]
Colin Patrick McCabe commented on HTRACE-275:
---------------------------------------------
bq. If user calls wrap or getTracerPool, that is ok against NullTracer?
{{NullTracer#wrap}} should work fine, since it's just using the wrapper classes
that call {{newScope}}, and we have overridden that in {{NullScope}}.
{{NullTracer#getTracerPool}} will return {{TracerPool.NULL_TRACER_POOL}}-- this
is not the default tracer pool, but it is a valid tracer pool.
bq. A subclass is returning an instance of superclass... \[in gettNullTracer\]
It's a static method, so this should be OK? The motivation for putting it in
{{Tracer.java}} rather than {{NullTracer.java}} was because I didn't want to
make {{NullTracer}} a public class (reduce API surface).
I looked at the Hadoop code, and I don't think we really need this patch there.
We fixed the null pointer exception we had earlier by correctly initializing
the tracer variable. I'll have to think about the patch-- like I said, I'm a
little worried that overuse of {{NullTracer}} in client code could cause us to
lose spans. Maybe there are some use-cases I haven't thought about...
> Add NullTracer which never creates a trace span
> -----------------------------------------------
>
> Key: HTRACE-275
> URL: https://issues.apache.org/jira/browse/HTRACE-275
> Project: HTrace
> Issue Type: Improvement
> Components: api
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
> Attachments: HTRACE-275.001.patch
>
>
> [~iwasakims] suggested adding a {{NullTracer}} which never creates a trace
> span. This would be more convenient than checking tracer objects against
> null in some cases.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
