neo4j performance compared to mysql (how can it be improved?)

I'm sorry you can't reproduce the results. However, on a MacBook Air (1.8 GHz i7, 4 GB RAM) with a 2 GB heap, GCR cache, but no warming of caches, and no other tuning, with a similarly sized dataset (1 million users, 50 friends per person), I repeatedly get approx 900 ms using the Traversal Framework on 1.9.2:

public class FriendOfAFriendDepth4{    private static final TraversalDescription traversalDescription =          Traversal.description()            .depthFirst()            .uniqueness( Uniqueness.NODE_GLOBAL )            .relationships( withName( "FRIEND" ), Direction.OUTGOING )            .evaluator( new Evaluator()            {                @Override                public Evaluation evaluate( Path path )                {                    if ( path.length() >= 4 )                    {                        return Evaluation.INCLUDE_AND_PRUNE;                    }                    return Evaluation.EXCLUDE_AND_CONTINUE;                }            } );    private final Index<Node> userIndex;    public FriendOfAFriendDepth4( GraphDatabaseService db )    {        this.userIndex = db.index().forNodes( "user" );    }    public Iterator<Path> getFriends( String name )    {        return traversalDescription.traverse(             userIndex.get( "name", name ).getSingle() )                .iterator();    }    public int countFriends( String name )    {        return  count( traversalDescription.traverse(             userIndex.get( "name", name ).getSingle() )                 .nodes().iterator() );    }}

Cypher is slower, but nowhere near as slow as you suggest: approx 3 seconds:

START person=node:user(name={name})MATCH (person)-[:FRIEND]->()-[:FRIEND]->()-[:FRIEND]->()-[:FRIEND]->(friend)RETURN count(friend)

Kind regards

ian

Yes, I believe the REST API is significantly slower than the regular bindings and therein lies your performance problem.