scylla-jmx/src/main/java/org/apache/cassandra/metrics/CacheMetrics.java

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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
/*
* Copyright 2015 Cloudius Systems
*
* Modified by Cloudius Systems
*/
package org.apache.cassandra.metrics;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import com.cloudius.urchin.api.APIClient;
import com.cloudius.urchin.metrics.APIMetrics;
import com.cloudius.urchin.metrics.DefaultNameFactory;
import com.cloudius.urchin.metrics.MetricNameFactory;
import com.yammer.metrics.core.Gauge;
import com.yammer.metrics.core.Meter;
/**
* Metrics for {@code ICache}.
*/
public class CacheMetrics {
/** Cache capacity in bytes */
public final Gauge<Long> capacity;
/** Total number of cache hits */
public final Meter hits;
/** Total number of cache requests */
public final Meter requests;
/** cache hit rate */
public final Gauge<Double> hitRate;
/** Total size of cache, in bytes */
public final Gauge<Long> size;
/** Total number of cache entries */
public final Gauge<Integer> entries;
private final AtomicLong lastRequests = new AtomicLong(0);
private final AtomicLong lastHits = new AtomicLong(0);
private APIClient c = new APIClient();
/**
* Create metrics for given cache.
*
* @param type
* Type of Cache to identify metrics.
* @param cache
* Cache to measure metrics
*/
public CacheMetrics(String type, final String url) {
MetricNameFactory factory = new DefaultNameFactory("Cache", type);
capacity = APIMetrics.newGauge(factory.createMetricName("Capacity"),
new Gauge<Long>() {
public Long value() {
return c.getLongValue("/cache_service/metrics/" + url
+ "/capacity");
}
});
hits = APIMetrics.newMeter("/cache_service/metrics/" + url
+ "/hits", factory.createMetricName("Hits"), "hits",
TimeUnit.SECONDS);
requests = APIMetrics.newMeter("/cache_service/metrics/" + url
+ "/requests", factory.createMetricName("Requests"),
"requests", TimeUnit.SECONDS);
hitRate = APIMetrics.newGauge(factory.createMetricName("HitRate"),
new Gauge<Double>() {
@Override
public Double value() {
return c.getDoubleValue("/cache_service/metrics/" + url
+ "/hit_rate");
}
});
size = APIMetrics.newGauge(factory.createMetricName("Size"),
new Gauge<Long>() {
public Long value() {
return c.getLongValue("/cache_service/metrics/" + url
+ "/size");
}
});
entries = APIMetrics.newGauge(factory.createMetricName("Entries"),
new Gauge<Integer>() {
public Integer value() {
return c.getIntValue("/cache_service/metrics/" + url
+ "/entries");
}
});
}
// for backward compatibility
@Deprecated
public double getRecentHitRate() {
long r = requests.count();
long h = hits.count();
try
{
return ((double)(h - lastHits.get())) / (r - lastRequests.get());
}
finally
{
lastRequests.set(r);
lastHits.set(h);
}
}
}