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https://issues.apache.org/jira/browse/FLINK-4245?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15424419#comment-15424419
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ASF GitHub Bot commented on FLINK-4245:
---------------------------------------
Github user StephanEwen commented on a diff in the pull request:
https://github.com/apache/flink/pull/2300#discussion_r75112407
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/metrics/groups/AbstractMetricGroup.java
---
@@ -83,9 +88,25 @@
//
------------------------------------------------------------------------
- public AbstractMetricGroup(MetricRegistry registry, String[] scope) {
+ public AbstractMetricGroup(MetricRegistry registry, String[] scope, A
parent) {
this.registry = checkNotNull(registry);
this.scopeComponents = checkNotNull(scope);
+ this.parent = parent;
+ }
+
+ public Map<String, String> getAllVariables() {
+ if (variables == null) { // avoid synchronization for common
case
--- End diff --
This "double check locking" does not work properly, unless you make the
variable `variables` volatile.
I am wondering if we should not simply initialize the map eagerly.
> Metric naming improvements
> --------------------------
>
> Key: FLINK-4245
> URL: https://issues.apache.org/jira/browse/FLINK-4245
> Project: Flink
> Issue Type: Improvement
> Components: Metrics
> Reporter: Stephan Ewen
>
> A metric currently has two parts to it:
> - The name of that particular metric
> - The "scope" (or namespace), defined by the group that contains the metric.
> A metric group actually always implicitly has a map of naming "tags", like:
> - taskmanager_host : <some-hostname>
> - taskmanager_id : <id>
> - task_name : "map() -> filter()"
> We derive the scope from that map, following the defined scope formats.
> For JMX (and some users that use JMX), it would be natural to expose that map
> of tags. Some users reconstruct that map by parsing the metric scope. JMX, we
> can expose a metric like:
> - domain: "taskmanager.task.operator.io"
> - name: "numRecordsIn"
> - tags: { "hostname" -> "localhost", "operator_name" -> "map() at
> X.java:123", ... }
> For many other reporters, the formatted scope makes a lot of sense, since
> they think only in terms of (scope, metric-name).
> We may even have the formatted scope in JMX as well (in the domain), if we
> want to go that route.
> [~jgrier] and [~Zentol] - what do you think about that?
> [~mdaxini] Does that match your use of the metrics?
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