denis-chudov commented on code in PR #957: URL: https://github.com/apache/ignite-3/pull/957#discussion_r943485342
########## modules/metrics/src/main/java/org/apache/ignite/internal/metrics/DistributionMetric.java: ########## @@ -0,0 +1,169 @@ +/* + * 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.ignite.internal.metrics; + +import static java.util.Collections.unmodifiableList; + +import java.util.ArrayList; +import java.util.List; +import java.util.concurrent.atomic.AtomicLongArray; +import java.util.concurrent.atomic.AtomicReferenceFieldUpdater; +import org.jetbrains.annotations.NotNull; +import org.jetbrains.annotations.Nullable; + +/** + * Distribution metric calculates counts of measurements that gets into each bounds interval. + * Note, that {@link #value()} will return array length of {@code bounds.length + 1}. + * Last element contains count of measurements bigger than most right value of bounds. + */ +public class DistributionMetric extends AbstractMetric implements CompositeMetric { + /** Count of measurement for each bound. */ + private final AtomicLongArray measurements; + + /** Bounds of measurements. */ + private final long[] bounds; + + /** List of scalar metrics. */ + private volatile List<Metric> scalarMetrics = null; + + /** + * The constructor. + * + * @param name Name. + * @param desc Description. + * @param bounds Bounds of the buckets. + */ + public DistributionMetric(String name, @Nullable String desc, @NotNull long[] bounds) { + super(name, desc); + + assert bounds != null && bounds.length > 0; + assert isSorted(bounds); + + this.bounds = bounds; + this.measurements = new AtomicLongArray(bounds.length + 1); + } + + /** + * Check whether given array is sorted. + * + * @param arr Array to check. + * @return {@code True} if array sorted, {@code false} otherwise. + */ + private static boolean isSorted(@NotNull long[] arr) { + if (arr.length < 2) { + return true; + } + + for (int i = 1; i < arr.length; i++) { + if (arr[i - 1] > arr[i]) { + return false; + } + } + + return true; + } + + /** + * Adds a value to the interval which the value belongs to. + * + * @param x Value. + */ + public void add(long x) { + assert x >= 0; + + //Expect arrays of few elements. + for (int i = 0; i < bounds.length; i++) { + if (x <= bounds[i]) { + measurements.incrementAndGet(i); + + return; + } + } + + measurements.incrementAndGet(bounds.length); + } + + /** {@inheritDoc} */ + public long[] value() { + long[] res = new long[measurements.length()]; + + for (int i = 0; i < measurements.length(); i++) { + res[i] = measurements.get(i); + } + + return res; + } + + /** {@inheritDoc} */ + @Override public @Nullable String getValueAsString() { + StringBuilder sb = new StringBuilder("["); + + List<Metric> scalarMetrics = asScalarMetrics(); + + for (int i = 0; i < scalarMetrics.size(); i++) { + LongMetric m = (LongMetric) scalarMetrics.get(i); + + sb.append(m.name()) + .append(':') + .append(m.value()); + + if (i < scalarMetrics.size() - 1) { + sb.append(", "); + } + } + + sb.append(']'); + + return sb.toString(); + } + + /** + * Bounds of the buckets of distribution. + * + * @return Bounds of the buckets of distribution. + */ + public long[] bounds() { + return bounds; + } + + /** {@inheritDoc} */ + @Override public List<Metric> asScalarMetrics() { + if (scalarMetrics == null) { + List<Metric> metrics = new ArrayList<>(); + + for (int i = 0; i < measurements.length(); i++) { + String from = i == 0 ? "0" : String.valueOf(bounds[i - 1]); + String to = i == measurements.length() - 1 ? "" : String.valueOf(bounds[i]); + + String name = new StringBuilder(from).append('_').append(to).toString(); + + final int index = i; + LongGauge gauge = new LongGauge(name, "Single distribution bucket", () -> measurements.get(index)); + + metrics.add(gauge); + } + + AtomicReferenceFieldUpdater<DistributionMetric, List> updater = Review Comment: actually this updater will be created only once on first call of `asScalarMetrics` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
