I know how to remove a vertex by id, but I need to delete multiple vertices (clean the db).
Deleting 1 v is like this:
ver = g.v(1)
g.removeVertex(ver)
you can try
g.V.each{g.removeVertex(it)}
g.commit()
In more recent terms as of Gremlin 2.3.0, removal of all vertices would be best accomplished with:
g.V.remove()
UPDATE: For version Gremlin 3.x you would use drop():
gremlin> graph = TinkerFactory.createModern()
==>tinkergraph[vertices:6 edges:6]
gremlin> g = graph.traversal()
==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard]
gremlin> g.V().drop().iterate()
gremlin> graph
==>tinkergraph[vertices:0 edges:0]
Note that drop() does not automatically iterate the Traversal as remove() did so you have to explicitly call iterate() for the deletion to occur. Iteration in the Gremlin Console is discussed in detail in this tutorial.
Also, consider that different graph systems will potentially have their own methods for more quickly and efficiently removing all data in that system. For example, JanusGraph has this approach:
JanusGraphFactory.drop(graph)
where "graph" is a JanusGraph instance you want cleared out.
If you are using Tinkerpop3 (Titan 1.0.0), as said before, the command is:
g.V().drop()
Why this did not work for me
This only works if you are using the Gremlin interactive REPL interface. Why? drop returns an iterator that must be traversed to be applied and the Gremlin REPL interface automatically iterates over returned iterators.
How I fixed it
If (like me) you are using an HTTP or WebSocket interface to Gremlin, you must explicitly iterate over the returned iterator:
g.V().drop().iterate()
Do not forget...
...to commit the transaction. In Titan, transactions are opened implicitly but must be closed explicitly:
g.tx().commit()
You can do it as follows;
graph.shutdown();
TitanCleanup.clear(graph);
Blueprints used to have a clear() method for this...
g.clear()
But it was recently removed:
In TinkerPop3:
The drop()-step (filter/sideEffect) is used to remove element and properties from the graph (i.e. remove).
g.V().drop()
In TinkerPop3, with Titan-1.0.0,
g.V().drop()
g.tx().commit() (commit the changes)
works for me. You can give a try
public class JanusGraphCleanup {
@Deprecated
public static void clear(JanusGraph graph) throws BackendException {
JanusGraphFactory.drop(graph);
}
}
来源：https://stackoverflow.com/questions/12814305/gremlin-remove-all-vertex