| /* |
| * 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. |
| */ |
| |
| package org.apache.cassandra.io.sstable.keycache; |
| |
| import java.util.Arrays; |
| import java.util.List; |
| |
| import org.apache.cassandra.io.sstable.AbstractMetricsProviders; |
| import org.apache.cassandra.io.sstable.GaugeProvider; |
| import org.apache.cassandra.io.sstable.format.SSTableReader; |
| |
| public class KeyCacheMetrics<R extends SSTableReader & KeyCacheSupport<R>> extends AbstractMetricsProviders<R> |
| { |
| public final static KeyCacheMetrics<?> instance = new KeyCacheMetrics<>(); |
| |
| @Override |
| protected R map(SSTableReader r) |
| { |
| if (r instanceof KeyCacheSupport<?>) |
| return (R) r; |
| return null; |
| } |
| |
| /** Key cache hit rate for this CF */ |
| private final GaugeProvider<Double> keyCacheHitRate = newGaugeProvider("KeyCacheHitRate", readers -> { |
| long hits = 0L; |
| long requests = 0L; |
| for (R sstable : readers) |
| { |
| hits += sstable.getKeyCache().getHits(); |
| requests += sstable.getKeyCache().getRequests(); |
| } |
| |
| return (double) hits / (double) Math.max(1, requests); |
| }); |
| |
| private final List<GaugeProvider<?>> gaugeProviders = Arrays.asList(keyCacheHitRate); |
| |
| public List<GaugeProvider<?>> getGaugeProviders() |
| { |
| return gaugeProviders; |
| } |
| } |