MapUpdater2.java

package aaa;

import java.util.HashMap;

/**
 * Use -Xmx30G -Xms30G for 100,000,000 rows
 */
public class MapUpdater2 {

    public static void main(String[] args) throws InterruptedException {
        if (args.length != 3) {
            throw new RuntimeException("Usage: MapUpdater2 <map_size_mil> <update_count_mil> <thread_count>");
        }
        int mapSize = Integer.parseInt(args[0]) * 1000000;
        int updCnt = Integer.parseInt(args[1]) * 1000000;
        int thCnt = Integer.parseInt(args[2]);

        HashMap<String, Row> map = new HashMap<>((int) (mapSize * 1.1));
        for (int i = 0; i < mapSize; i++) {
            String dom = getDomain(i);
            map.put(dom, new Row());
        }
        System.out.println("Map Init Done");
        update(map, updCnt, thCnt);
        update(map, updCnt, thCnt);
        update(map, updCnt, thCnt);
        update(map, updCnt, thCnt);
    }

    static void update(HashMap<String, Row> map, int updCnt, int thCnt) throws InterruptedException {
        Thread[] tt = new Thread[thCnt];
        for (int i = 0; i < thCnt; i++) {
            tt[i] = new Thread(new Updater(map, updCnt, thCnt, i));
        }
        long s1 = System.currentTimeMillis();
        for (Thread t : tt) {
            t.start();
        }
        for (Thread t : tt) {
            t.join();
        }
        long s2 = System.currentTimeMillis();
        System.out.println(s2 - s1);
    }

    static class Row {
        public long v1;

        @Override
        public String toString() {
            return "row.v1: " + v1;
        }
    }

    static String getDomain(int i) {
        if (i < 10) {
            return "d00000000" + i;
        } else if (i < 100) {
            return "d0000000" + i;
        } else if (i < 1000) {
            return "d000000" + i;
        } else if (i < 10000) {
            return "d00000" + i;
        } else if (i < 100000) {
            return "d0000" + i;
        } else if (i < 1000000) {
            return "d000" + i;
        } else if (i < 10000000) {
            return "d00" + i;
        } else if (i < 100000000) {
            return "d0" + i;
        } else {
            return "d" + i;
        }
    }

    static class Updater implements Runnable {
        HashMap<String, Row> map;
        int updCnt;
        int thCnt;
        int part;

        public Updater(HashMap<String, Row> map, int updCnt, int thCnt, int part) {
            this.map = map;
            this.updCnt = updCnt;
            this.thCnt = thCnt;
            this.part = part;
        }

        @Override
        public void run() {
            update();
        }

        void update() {
            for (int i = 0; i < updCnt; i++) {
                if (i % thCnt != part) continue;
                String dom = getDomain(i);
                Row row = map.get(dom);
                row.v1 += 1L;
            }
        }
    }
}
//    Map Init Done
//        133
//        83
//        66
//        66