mysql neo4j,与MySQL相比，neo4j的性能（如何改进？）

This is a follow up to can't reproduce/verify the performance claims in graph databases and neo4j in action books. I have updated the setup and tests, and don't want to change the original question too much.

Short version: while trying to verify the performance claims made in the 'Graph Database' book I came to the following results (querying a random dataset containing n people, with 50 friends each):

My results for 100k people

depth neo4j mysql python

1 0.010 0.000 0.000

2 0.018 0.001 0.000

3 0.538 0.072 0.009

4 22.544 3.600 0.330

5 1269.942 180.143 0.758

"*": single run only

My results for 1 million people

depth neo4j mysql python

1 0.010 0.000 0.000

2 0.018 0.002 0.000

3 0.689 0.082 0.012

4 30.057 5.598 1.079

5 1441.397* 300.000 9.791

"*": single run only

Using 1.9.2 on a 64bit ubuntu I have setup neo4j.properties with these values:

neostore.nodestore.db.mapped_memory=250M

neostore.relationshipstore.db.mapped_memory=2048M

and neo4j-wrapper.conf with:

wrapper.java.initmemory=1024

wrapper.java.maxmemory=8192

My query to neo4j looks like this (using the REST api):

start person=node:node_auto_index(noscenda_name="person123") match (person)-[:friend]->()-[:friend]->(friend) return count(distinct friend);

Node_auto_index is in place, obviously

Is there anything I can do to speed neo4j up (to be faster then mysql)?

And also there is another benchmark in Stackoverflow with same problem.

解决方案

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 userIndex;

public FriendOfAFriendDepth4( GraphDatabaseService db )

{

this.userIndex = db.index().forNodes( "user" );

}

public Iterator 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