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/*
* Copyright DataStax, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.datastax.driver.core;
/**
* A {@code PercentileTracker} that aggregates all measurements into a single histogram.
*
* This gives you global latency percentiles for the whole cluster, meaning that latencies of
* slower hosts will tend to appear in higher percentiles.
*/
public class ClusterWidePercentileTracker extends PercentileTracker {
private volatile Cluster cluster;
private ClusterWidePercentileTracker(
long highestTrackableLatencyMillis,
int numberOfSignificantValueDigits,
int minRecordedValues,
long intervalMs) {
super(
highestTrackableLatencyMillis,
numberOfSignificantValueDigits,
minRecordedValues,
intervalMs);
}
@Override
public void onRegister(Cluster cluster) {
this.cluster = cluster;
}
@Override
protected Cluster computeKey(Host host, Statement statement, Exception exception) {
return cluster;
}
/**
* Returns a builder to create a new instance.
*
* @param highestTrackableLatencyMillis the highest expected latency. If a higher value is
* reported, it will be ignored and a warning will be logged. A good rule of thumb is to set
* it slightly higher than {@link SocketOptions#getReadTimeoutMillis()}.
* @return the builder.
*/
public static Builder builder(long highestTrackableLatencyMillis) {
return new Builder(highestTrackableLatencyMillis);
}
/** Helper class to build {@code PerHostPercentileTracker} instances with a fluent interface. */
public static class Builder
extends PercentileTracker.Builder {
Builder(long highestTrackableLatencyMillis) {
super(highestTrackableLatencyMillis);
}
@Override
protected Builder self() {
return this;
}
@Override
public ClusterWidePercentileTracker build() {
return new ClusterWidePercentileTracker(
highestTrackableLatencyMillis,
numberOfSignificantValueDigits,
minRecordedValues,
intervalMs);
}
}
}