com.palantir.atlasdb.keyvalue.cassandra.pool.DistributionOutlierController Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of atlasdb-cassandra Show documentation
Show all versions of atlasdb-cassandra Show documentation
Palantir open source project
The newest version!
/*
* (c) Copyright 2020 Palantir Technologies Inc. All rights reserved.
*
* 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.palantir.atlasdb.keyvalue.cassandra.pool;
import com.codahale.metrics.CachedGauge;
import com.codahale.metrics.Clock;
import com.codahale.metrics.Gauge;
import com.google.common.annotations.VisibleForTesting;
import com.palantir.atlasdb.metrics.MetricPublicationFilter;
import com.palantir.logsafe.exceptions.SafeIllegalStateException;
import java.time.Duration;
import java.util.List;
import java.util.Objects;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
/**
* Given a series of gauge metrics, allows for the retrieval for the mean. Furthermore allows for the generation of
* {@link MetricPublicationFilter}s that identify whether any specific values exceed a tolerance value from the mean.
*/
class DistributionOutlierController {
@VisibleForTesting
static final Duration REFRESH_INTERVAL = Duration.ofSeconds(30);
private final Set> gauges;
private final double minimumMeanMultiple;
private final double maximumMeanMultiple;
private final Gauge meanGauge;
@VisibleForTesting
DistributionOutlierController(Clock clock, double minimumMeanMultiple, double maximumMeanMultiple) {
this.gauges = ConcurrentHashMap.newKeySet();
this.minimumMeanMultiple = minimumMeanMultiple;
this.maximumMeanMultiple = maximumMeanMultiple;
this.meanGauge = new CachedGauge(clock, REFRESH_INTERVAL.toNanos(), TimeUnit.NANOSECONDS) {
@Override
protected Double loadValue() {
List gaugeValues = gauges.stream()
.map(Gauge::getValue)
.filter(Objects::nonNull)
.collect(Collectors.toList());
if (gaugeValues.isEmpty()) {
return null;
}
return gaugeValues.stream()
.mapToLong(x -> x)
.average()
.orElseThrow(() -> new SafeIllegalStateException("Improperly handled average of 0 values"));
}
};
}
static DistributionOutlierController create(double minimumMeanMultiple, double maximumMeanMultiple) {
return new DistributionOutlierController(Clock.defaultClock(), minimumMeanMultiple, maximumMeanMultiple);
}
Gauge getMeanGauge() {
return meanGauge;
}
MetricPublicationFilter registerAndCreateFilter(Gauge gauge) {
gauges.add(gauge);
return () -> shouldPublishIndividualGaugeMetric(gauge);
}
private boolean shouldPublishIndividualGaugeMetric(Gauge constituentGauge) {
long value = constituentGauge.getValue();
Double mean = meanGauge.getValue();
return mean != null && (value > mean * maximumMeanMultiple || value < mean * minimumMeanMultiple);
}
}