Titan adding vertex using multi-threads - titan

Question

I am using Titan 1 with tinkerpop3 and gremlin.
For small jobs I use threads who are basically doing:
myNode = g.V().has(somthing)
//some tests
newNode = graph.addVertex(someProperties)
g.V(myNode).addEdge(newNode)
During the creation of the edge I get this exceptio:
java.lang.IllegalStateException: The vertex or type is not associated with this transaction [v[41025720]]
I understand that my newNode is (kind of) not on the transaction of my thread.
How can I refresh the transaction scope, or add my newnode to the current transaction?
Thanks

Answer 1

First off I would recommend reading chapter 9 of the titan doc which deals with transactions in greater detail.
For your specific problem all you need to do is create a transaction and have all threads work on that transaction. Taking from the docs directly what you need is:
TitanGraph g = TitanFactory.open(CONFIG);
TransactionalGraph tx = g.newTransaction();
Thread[] threads = new Thread[10];
for (int i=0;i<threads.length;i++) {
threads[i]=new Thread(new DoSomething(tx));
threads[i].start();
}
for (int i=0;i<threads.length;i++) threads[i].join();
tx.commit();
This will get all threads to work on the same transaction and have access to the same nodes and edges.
Without doing this Titan will automatically create a new transaction for each different thread accessing the graph. Which means each thread will be working with different new nodes, edges, etc. . .
Example DoSomething
DoSomething(TransactionalGraph tx){
tx.addVertex();
}