jiajunwang commented on a change in pull request #636: Simply and enhance the
RebalanceLatencyGauge so it can be used in multi-threads.
URL: https://github.com/apache/helix/pull/636#discussion_r352815776
##########
File path:
helix-core/src/main/java/org/apache/helix/monitoring/metrics/implementation/RebalanceLatencyGauge.java
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@@ -50,24 +53,24 @@ public RebalanceLatencyGauge(String metricName, long
slidingTimeWindow) {
@Override
public void startMeasuringLatency() {
reset();
- _startTime = System.currentTimeMillis();
+ _startTime.set(System.currentTimeMillis());
}
/**
* WARNING: this method is not thread-safe.
*/
@Override
public void endMeasuringLatency() {
- if (_startTime == VALUE_NOT_SET || _endTime != VALUE_NOT_SET) {
+ if (_startTime.get() == VALUE_NOT_SET) {
LOG.error(
"Needs to call startMeasuringLatency first! Ignoring and resetting
the metric. Metric name: {}",
_metricName);
- reset();
return;
}
- _endTime = System.currentTimeMillis();
- _lastEmittedMetricValue = _endTime - _startTime;
- updateValue(_lastEmittedMetricValue);
+ synchronized (this) {
Review comment:
No, the caller is usually reading the data from a different thread. If you
make this output value thread local, you will always get the init value (-1).
So it has to be a normal value.
The same to the metric object too.
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