OrientDB client CPU goes over 100% with ODB2.2.20

Question

I want to load lots of data into Orient DB with multiple threads. I'm using OrientDB 2.2.20 and Java 1.8.0_131 to run below sample test client. But when I run this client with 5 threads and 10000 samples then the client's CPU usage goes over 100% and the process becomes almost dead.

Actually I wanted to use graph APIs to create huge number of vertices and edges between them. But I read in some post that for massive inserts use document API and set the in & out pointers using doc APIs. Hence tried this program.

Could someone point what is wrong in the code?

public OrientDBTestClient(){

    db = new ODatabaseDocumentTx(url).open(userName, password);
}

public static void main(String[] args) throws Exception{

    int threadCnt = Integer.parseInt(args[0]);
    OrientDBTestClient client = new OrientDBTestClient();

    try {

        db.declareIntent(new OIntentMassiveInsert());

        Thread[] threads = new Thread[threadCnt];
        for (int i = 0; i < threadCnt; i++) {
            Thread loadStatsThread = new Thread(client.new LoadTask(Integer.parseInt(args[1])));
            loadStatsThread.setName("LoadTask" + (i + 1));
            loadStatsThread.start();
            threads[i] = loadStatsThread;
        }
    }
    catch(Exception e){
        e.printStackTrace();
    }
}

private class LoadTask implements Runnable{

    public int count = 0;

    public LoadTask(int count){
        this.count = count;
    }

    public void run(){
        long start = System.currentTimeMillis();
        try{
            db.activateOnCurrentThread();
            for(int i = 0; i < count; ++ i){
                storeStatsInDB(i +"");
            }
        }
        catch(Exception e){
            log.println("Error in LoadTask : " + e.getMessage());
            e.printStackTrace();
        }
        finally {
            db.commit();
            System.out.println(Thread.currentThread().getName() + " loaded: " + count + " services in: "  + (System.currentTimeMillis() - start) + "ms");
        }
    }
}

public void storeStatsInDB(String id) throws Exception{

    try{
        long start = System.currentTimeMillis();

        ODocument doc = db.newInstance();
        doc.reset();
        doc.setClassName("ServiceStatistics");

        doc.field("serviceID", id);
        doc.field("name", "Service=" + id);

        doc.save();
    }
    catch(Exception e){
        log.println("Exception :" + e.getMessage());
        e.printStackTrace();
    }

}

Answer 1

db instances aren't sharable between threads. You have two choices:

• create an instance for each thread
• use the pool (my first choice): http://orientdb.com/docs/last/Java-Multi-Threading.html#working-with-databases

The following example is extracted from internal tests:

pool = new OPartitionedDatabasePool("remote:localshot/test", "admin", "admin");
Runnable acquirer = () -> {

  ODatabaseDocumentTx db = pool.acquire();

  try {

    List<ODocument> res = db.query(new OSQLSynchQuery<>("SELECT * FROM OUser"));


  } finally {

    db.close();
  }

};

//spawn 20 threads
List<CompletableFuture<Void>> futures = IntStream.range(0, 19).boxed().map(i -> CompletableFuture.runAsync(acquirer))
    .collect(Collectors.toList());

futures.forEach(cf -> cf.join());`