HELP2113.java

/*
 * Copyright 2016 MongoDB, Inc.
 *
 * 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.
 *
 */

import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;
import org.bson.RawBsonDocument;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.Consumer;

import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;

public class HELP2113 {

    public static void main(String[] args) throws Exception {
        String databaseName = args[1];
        String collectionName = args[2];
        MongoClient client = new MongoClient(new MongoClientURI(args[0]));
        MongoDatabase database = client.getDatabase(databaseName);
        MongoCollection<Document> collection = database.getCollection(collectionName);

        load(collection);

        System.out.println("Warming up...");
        for (int i = 0; i < 5; i++) {
            dump(collection);
            System.out.print('.');
        }

        System.out.println();
        System.out.println("Starting...");
        final int runs = 20;
        long totalElapsedMillis = 0;
        for (int i = 0; i < runs; i++) {
            long elapsedMillis = dump(collection);
            totalElapsedMillis += elapsedMillis;
            System.out.println(elapsedMillis + " ms");
        }

        System.out.println();
        System.out.println("Average: " + totalElapsedMillis / runs + " ms");

        System.out.println("All done");
    }

    private static void load(final MongoCollection<Document> collection) {
        long count = collection.count();
        if (count != 0) {
            System.out.println("Skipping loading phase as collection already contains " + count + " documents");
            return;
        }

        System.out.println("Starting loading phase");
        Random random = new Random();
        byte[] bytes = new byte[1000];
        List<Document> documents = new ArrayList<>(1024);
        for (int i = 0; i < 1000 * 1000; i++) {
            random.nextBytes(bytes);
            documents.add(new Document("_id", i).append("bin", bytes));
            if (documents.size() == 1000) {
                collection.insertMany(documents);
                documents.clear();
            }
        }

        System.out.println("Loaded documents");
    }

    private static long dump(final MongoCollection<Document> documentCollection) throws IOException, InterruptedException {
        File tempFile = File.createTempFile("HELP2113", ".bson", new File("/tmp"));
        tempFile.deleteOnExit();
        OutputStream os = new BufferedOutputStream(new FileOutputStream(tempFile), 1024 * 32);
        try {
            MongoCollection<RawBsonDocument> collection = documentCollection.withDocumentClass(RawBsonDocument.class);
            long start;
            BlockingQueue<RawBsonDocument> blockingQueue = new ArrayBlockingQueue<RawBsonDocument>(12000);

            AtomicBoolean done = new AtomicBoolean(false);
            start = System.nanoTime();

            Thread t = new Thread(() -> {
                try {
                    RawBsonDocument cur = blockingQueue.poll(1, MILLISECONDS);
                    while (cur != null || !done.get()) {
                        if (cur != null) {
                            os.write(cur.getByteBuffer().array());
                        }
                        cur = blockingQueue.poll(1, MILLISECONDS);
                    }
                } catch (Throwable e) {
                    e.printStackTrace();
                }
            });

            t.start();

            collection.find().batchSize(Integer.MAX_VALUE).forEach((Consumer<RawBsonDocument>) cur -> {
                try {
                    blockingQueue.put(cur);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            });

            done.set(true);
            t.join();

            return TimeUnit.MILLISECONDS.convert(System.nanoTime() - start, NANOSECONDS);
        } finally {
            os.close();
        }

    }
}