Add relation in existing node

[Navrattan Yadav]

Hi ...

     Currently we have 1.5 million node and one relation : KNOW between them.  

    Basic Model is : when a user register we add KNOW relation to all his friends.  (friends are :phone book friends)

    Now its getting slow as user increase. so we want to add more relation based on : COUNTRY,  SOCIAL NETWORK, CITY, COLLEGE ETC.

   so we need to add these relation in existing node without blocking database by running a separate thread.

  Please suggest some way,some query . how we can do this....

[Michael Hunger]

You have to share more details.

what versions do you use

what is your stack

what APIs do you use

share the code to create the relationships

what is getting slow

how many concurrent users do you have

etc.

Sometimes a slowdown is related to doing just one single update per transaction and having millions of those tiny transactions.

So it makes sense to aggregate those changes into larger chunks, e.g. all create your knows relationships in one TX (and the other ones too).

Perhaps something that might help you: http://maxdemarzi.com/2013/09/05/scaling-writes/

Michael

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[Navrattan Yadav]

Neo4j version  :  2.0.0-M06 .

Operating System : linux

Ram : 4GB

 

sir we get slow when we get 2nd degree friends for a user.Then most of People Suggest to create more relation :

So we are creating more relation to make it faster.

Code for creating relation : Using Java API :

public void addFriend(Person otherPerson) {

if (!this.equals(otherPerson)) {

                        //check if already created

Relationship friendRel = getFriendRelationshipTo(otherPerson);

if (friendRel == null) {

underlyingNode.createRelationshipTo( otherPerson.getUnderlyingNode(), KNOW);

}

}

}

private Relationship getFriendRelationshipTo(Person otherPerson) {

Node otherNode = otherPerson.getUnderlyingNode();

for (Relationship rel : underlyingNode.getRelationships(Direction.OUTGOING,KNOW)) {

if (rel.getOtherNode(underlyingNode).equals(otherNode)) {

return rel;

}

}

return null;

}

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Thanks and Regards

Navrattan Yadav

[Michael Hunger]

How many knows relationships do you have per person?

I think you should also check your configuration, 4GB of RAM is a bit on the low side, you might end up using swap all the time.

You should have enough non-heap RAM for some decent memory mapping of your store-files

And enough heap for sensible high level caches (e.g. 4G-8G HEAP)

So in total a machine with 16-32G heap would make more sense.

Also Upgrade to Neo4j 2.0 to have a stable baseline.

And if you add many friends at once I would do all those rel-checks at once too, so instead of iterating over all rels 100 times and checking them against a single person.

You iterate over them once and remove already existing friends from a hashset.

something like:

Set<Node> filterNewFriends(Set<Node> potentialFriends, Node underlyingNode) {

for (Relationship rel : underlyingNode.getRelationships(Direction.OUTGOING,KNOW)) {

potentialFriends.remove(rel.getEndNode());

}

return potentialFriends;

}

and then only create relationships to all those friends that have been returned.