how to insert a document without creating new mongodb connection?

Question

I am trying to develop a java project using mongodb as a database. I have 2 methods (threaded, without thread)

    //myMongoHelper, for connection
    //mydbhelper, threaded insertion

    myMongoHelper m = new myMongoHelper("localhost",27017,"mydb","mycoll");
    int id=100;
    Thread t = new Thread(new mydbhelper(new BasicDBObject()));
    while(id>0){
        t.start();
        t = new Thread(new mydbhelper(new BasicDBObject()));
        id--;
    }
    t.join();
    m.myclose();

and

        int id =100;
        mongoClient = new MongoClient("localhost" , 27017 );
        DBCollection coll = mongoClient.getDB( "mydb" ).getCollection("mycoll");
        while(id>0){
            coll.insert(new BasicDBObject());
            id--;
        }
        mongoClient.close();

$mongod shell shows XX connections now open while execution of a code, and by default it terminates all connections at the end of java execution.

So I want to know,

1. open connections affects mongodb database and how?
2. is it possible to terminate a thread after insertion to decrease a count of connections?
3. Is threading is better for mongodb operations specially for insertion?

Please improve my code.

Answer 1

I'm going to answer all of them together, every new connection takes huge amount of resource in order to initialize, therefore keep them as low as possible.

Instead of creating a new connection for each thread, use a single connection and distribute your query! you can distribute your queries with this way! also you can use bulk insert in order to insert huge amount of docs.

    DBCollection coll = mongoClient.getDB( "mydb" ).getCollection("mycoll");
    ArrayList<BasicDBObject> dbos = new ArrayList<BasicDBObject>();
    while(id>0){
        dbs.add(new BasicDBObject());
        id--;
    }
    coll.insert(dbos);