Adding artsiomkorzun's solution
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artsiomkorzun
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calculate_average_artsiomkorzun.sh
Executable file
20
calculate_average_artsiomkorzun.sh
Executable file
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#!/bin/sh
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#
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# Copyright 2023 The original authors
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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JAVA_OPTS="-XX:+UseParallelGC"
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time java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_artsiomkorzun
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/*
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* Copyright 2023 The original authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package dev.morling.onebrc;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.nio.MappedByteBuffer;
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import java.nio.channels.FileChannel;
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import java.nio.file.Files;
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import java.nio.file.Path;
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import java.nio.file.StandardOpenOption;
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import java.util.Arrays;
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import java.util.Comparator;
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import java.util.function.Consumer;
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import java.util.stream.IntStream;
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public class CalculateAverage_artsiomkorzun {
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private static final Path FILE = Path.of("./measurements.txt");
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private static final long FILE_SIZE = size(FILE);
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private static final int SEGMENT_SIZE = 16 * 1024 * 1024;
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private static final int SEGMENT_COUNT = (int) ((FILE_SIZE + SEGMENT_SIZE - 1) / SEGMENT_SIZE);
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private static final int SEGMENT_OVERLAP = 1024;
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public static void main(String[] args) throws Exception {
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/*for (int i = 0; i < 10; i++) {
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long start = System.currentTimeMillis();
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execute();
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long end = System.currentTimeMillis();
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System.err.println("Time: " + (end - start));
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}*/
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execute();
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}
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private static void execute() {
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Aggregates aggregates = IntStream.range(0, SEGMENT_COUNT)
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.parallel()
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.mapToObj(CalculateAverage_artsiomkorzun::aggregate)
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.reduce(new Aggregates(), CalculateAverage_artsiomkorzun::merge)
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.sort();
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print(aggregates);
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}
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private static Aggregates aggregate(int segment) {
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long position = (long) SEGMENT_SIZE * segment;
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int size = (int) Math.min(SEGMENT_SIZE + SEGMENT_OVERLAP, FILE_SIZE - position);
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int limit = Math.min(SEGMENT_SIZE, size - 1);
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MappedByteBuffer buffer = map(position, size); // leaking until gc
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if (position > 0) {
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next(buffer);
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}
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Aggregates aggregates = new Aggregates();
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Row row = new Row();
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while (buffer.position() <= limit) {
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parse(buffer, row);
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aggregates.add(row);
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}
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return aggregates;
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}
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private static Aggregates merge(Aggregates lefts, Aggregates rights) {
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Aggregates to = (lefts.size() < rights.size()) ? rights : lefts;
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Aggregates from = (lefts.size() < rights.size()) ? lefts : rights;
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from.visit(to::merge);
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return to;
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}
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private static void print(Aggregates aggregates) {
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StringBuilder builder = new StringBuilder(aggregates.size() * 15 + 32);
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builder.append("{");
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aggregates.visit(aggregate -> {
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if (builder.length() > 1) {
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builder.append(", ");
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}
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builder.append(aggregate);
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});
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builder.append("}");
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System.out.println(builder);
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}
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private static long size(Path file) {
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try {
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return Files.size(file);
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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}
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private static MappedByteBuffer map(long position, int size) {
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try (FileChannel channel = FileChannel.open(FILE, StandardOpenOption.READ)) {
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return channel.map(FileChannel.MapMode.READ_ONLY, position, size); // leaking until gc
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} catch (Throwable e) {
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throw new RuntimeException(e);
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}
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}
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private static void next(ByteBuffer buffer) {
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while (buffer.get() != '\n') {
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// continue
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}
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}
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private static void parse(ByteBuffer buffer, Row row) {
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int index = 0;
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byte b;
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while ((b = buffer.get()) != ';') {
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row.station[index++] = b;
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}
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row.length = index;
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double value = 0;
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double multiplier = 1;
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b = buffer.get();
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if (b == '-') {
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multiplier = -1;
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} else {
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assert b >= '0' && b <= '9';
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value = b - '0';
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}
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while ((b = buffer.get()) != '.') {
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assert b >= '0' && b <= '9';
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value = 10 * value + (b - '0');
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}
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b = buffer.get();
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assert b >= '0' && b <= '9';
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value = 10 * value + (b - '0');
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b = buffer.get();
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assert b == '\n';
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row.temperature = value * multiplier;
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}
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private static class Row {
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final byte[] station = new byte[256];
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int length;
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double temperature;
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@Override
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public String toString() {
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return new String(station, 0, length) + ":" + temperature;
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}
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}
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private static class Aggregate implements Comparable<Aggregate> {
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final byte[] station;
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double min;
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double max;
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double sum;
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double count;
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public Aggregate(byte[] station, int length, double temperature) {
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this.station = Arrays.copyOf(station, length);
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this.min = temperature;
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this.max = temperature;
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this.sum = temperature;
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this.count = 1;
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}
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public void add(double temperature) {
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min = Math.min(min, temperature);
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max = Math.max(max, temperature);
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sum += temperature;
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count++;
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}
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public void merge(Aggregate right) {
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min = Math.min(min, right.min);
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max = Math.max(max, right.max);
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sum += right.sum;
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count += right.count;
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}
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@Override
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public int compareTo(Aggregate that) {
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byte[] lhs = this.station;
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byte[] rhs = that.station;
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int limit = Math.min(lhs.length, rhs.length);
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for (int offset = 0; offset < limit; offset++) {
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int left = lhs[offset];
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int right = rhs[offset];
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if (left != right) {
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return (left & 0xFF) - (right & 0xFF);
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}
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}
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return lhs.length - rhs.length;
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}
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@Override
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public String toString() {
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return new String(station) + "=" + round(min) + "/" + round(sum / count) + "/" + round(max);
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}
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private static double round(double v) {
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return Math.round(v) / 10.0;
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}
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}
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private static class Aggregates {
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private static final int GROW_FACTOR = 4;
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private static final float LOAD_FACTOR = 0.55f;
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private Aggregate[] aggregates = new Aggregate[1024];
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private int limit = (int) (aggregates.length * LOAD_FACTOR);
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private int size;
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public int size() {
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return size;
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}
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public void visit(Consumer<Aggregate> consumer) {
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if (size > 0) {
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for (Aggregate aggregate : aggregates) {
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if (aggregate != null) {
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consumer.accept(aggregate);
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}
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}
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}
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}
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public void add(Row row) {
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byte[] station = row.station;
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int length = row.length;
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double temperature = row.temperature;
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int hash = hash(station, length);
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int index = hash & (aggregates.length - 1);
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while (true) {
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Aggregate aggregate = aggregates[index];
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if (aggregate == null) {
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aggregates[index] = new Aggregate(station, length, temperature);
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if (++size >= limit) {
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grow();
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}
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break;
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}
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if (equal(station, length, aggregate.station, aggregate.station.length)) {
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aggregate.add(temperature);
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break;
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}
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index = (index + 1) & (aggregates.length - 1);
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}
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}
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public void merge(Aggregate right) {
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byte[] station = right.station;
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int hash = hash(station, station.length);
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int index = hash & (aggregates.length - 1);
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while (true) {
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Aggregate aggregate = aggregates[index];
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if (aggregate == null) {
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aggregates[index] = right;
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if (++size >= limit) {
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grow();
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}
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break;
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}
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if (equal(station, station.length, aggregate.station, aggregate.station.length)) {
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aggregate.merge(right);
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break;
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}
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index = (index + 1) & (aggregates.length - 1);
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}
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}
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public Aggregates sort() {
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Arrays.parallelSort(aggregates, Comparator.nullsLast(Aggregate::compareTo));
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return this;
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}
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private void grow() {
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Aggregate[] oldAggregates = aggregates;
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aggregates = new Aggregate[oldAggregates.length * GROW_FACTOR];
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limit = (int) (aggregates.length * LOAD_FACTOR);
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for (Aggregate aggregate : oldAggregates) {
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if (aggregate != null) {
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int hash = hash(aggregate.station, aggregate.station.length);
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int index = hash & (aggregates.length - 1);
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while (aggregates[index] != null) {
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index = (index + 1) & (aggregates.length - 1);
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}
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aggregates[index] = aggregate;
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}
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}
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}
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private static int hash(byte[] array, int length) {
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int hash = 0;
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for (int i = 0; i < length; i++) {
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hash = 71 * hash + array[i];
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}
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return hash;
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}
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private static boolean equal(byte[] left, int leftLength, byte[] right, int rightLength) {
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if (leftLength != rightLength) {
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return false;
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}
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for (int i = 0; i < leftLength; i++) {
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if (left[i] != right[i]) {
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return false;
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}
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}
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return true;
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}
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}
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}
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