Re: [Neo4j] Suggestions on how to order relationships?
how about weight? On Thu, Jan 19, 2012 at 6:23 PM, Aseem Kishore aseem.kish...@gmail.com wrote: Hi there, Take a Facebook-like example, where users can like different movies/music/celebs/etc. Suppose we want to let users drag-and-drop these movies/etc. on their profile pages, to let them e.g. show their favorite movies first. How would you guys recommend achieving that in Neo4j? If possible, I'd like to avoid creating a node for every relationship (redundancy/overhead as we do this more and more). I can't think of anything better than putting properties on the relationship. Maybe index numbers (e.g. rel D might have index: 0, rel B might have index: 1, etc.), but that's essentially reordering an array, which sucks. The other option that thus came to mind was to mimic a linked list: have an after property that contains the ID of the relationship this one comes after (and/or maybe a before property instead or in addition). Just wondering if there are better ideas! Thanks. =) Aseem ___ NOTICE: THIS MAILING LIST IS BEING SWITCHED TO GOOGLE GROUPS, please register and consider posting at https://groups.google.com/forum/#!forum/neo4j Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best wishes, Linan Wang Architect, Programmer, PhD ___ NOTICE: THIS MAILING LIST IS BEING SWITCHED TO GOOGLE GROUPS, please register and consider posting at https://groups.google.com/forum/#!forum/neo4j Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Using in-memory DB for unit tests
Why call tx.failure in close db?
On Wednesday, November 30, 2011, Jon Walton jon.w.wal...@gmail.com wrote:
Greetings - I have started my first project using neo4j, and am having
some
trouble with unit tests. I must be missing something, but when I
retrieve
a node using an incoming direction, I am unable to get properties from
that
node.The first test works fine, the second one fails with a
NotFoundException on the property asn. (although it does find the
end-node with no trouble) Can anyone point out what I am doing wrong?
Thanks,
Jon
/**
* $Id$
*/
package com.mcafee.tsw.webgraph;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.test.ImpermanentGraphDatabase;
/**
*/
public class TestMe {
private GraphDatabaseService svc;
private Transaction tx;
/**
* @throws java.lang.Exception
*/
@Before
public void initDB() throws Exception {
svc = new ImpermanentGraphDatabase();
tx = svc.beginTx();
}
/**
* @throws java.lang.Exception
*/
@After
public void closeDB() throws Exception {
tx.failure();
tx.finish();
svc.shutdown();
svc = null;
}
// This one works.
@Test
public void testOutgoing() {
Node network = svc.createNode();
Node as = svc.createNode();
as.setProperty(asn, 123);
network.createRelationshipTo(as, IPAddressRelationshipType.AS);
System.out.println(network.getSingleRelationship(IPAddressRelationshipType.AS,
Direction.OUTGOING)
.getEndNode().getProperty(asn));
}
// This one results in a not found exception on the 'asn' property.
@Test
public void testIncoming() {
Node network = svc.createNode();
Node as = svc.createNode();
as.setProperty(asn, 123);
as.createRelationshipTo(network, IPAddressRelationshipType.AS);
System.out.println(network.getSingleRelationship(IPAddressRelationshipType.AS,
Direction.INCOMING)
.getEndNode().getProperty(asn));
}
}
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Re: [Neo4j] How to boost performance?
model would suffice. Anything I could do to improve this? Regards ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best wishes, Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Neo4j upcoming features importance poll
the top feature i want: node insertion with checking of uniq external id: get_or_create On Sat, Nov 19, 2011 at 11:39 AM, Pablo Pareja ppar...@era7.com wrote: Hi all, I was thinking it'd be cool to create a sort of a poll in order to know which features (that are missing right now...) are the most important ones for the community. I just did a quick google search for free online poll creation platforms and found doodle site, (btw do you know a better site to do this?). The address for the poll is: http://www.doodle.com/wg8k77vwq6b654bv So far I just added three features that came to my mind while I was creating it, so please say which features you're missing and I'll add them so that we can all vote for them or not. What do you think about all this? Cheers, Pablo -- Pablo Pareja Tobes My site http://about.me/pablopareja LinkedIn http://www.linkedin.com/in/pabloparejatobes Twitter http://www.twitter.com/pablopareja Creator of Bio4j -- http://www.bio4j.com http://www.ohnosequences.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best wishes, Linan Wang Architect, Programmer, PhD ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Activity Streams and Twitter Sample App
one more solution. set a sampling_ratio, say 10: Person1.outgoing(:follows).outgoing(:tweeted).depth(2).filter(position.length()== 2;) .prune(position.returnedNodesCount() 100 * sampling_ratio) then do a sort based on timestamp. the goal is not to get the perfect result but *good enough* ones depends on your experience. On Thu, Nov 3, 2011 at 4:48 PM, maxdemarzi maxdema...@gmail.com wrote: Came up with another possibility: G) Store the Latest 100 tweeted relationship ids with dates as a property of the User Node, and a custom Breadth First Traversal that evaluates the list of every follower's latest 100 tweets before deciding which relationships to follow. -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Activity-Streams-and-Twitter-Sample-App-tp3477669p3477693.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best wishes, Linan Wang Architect, Programmer, PhD ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] some questions
to clear the full db, stop the server and delete the files in data folder :) On Fri, Oct 28, 2011 at 3:57 PM, Marko Rodriguez okramma...@gmail.com wrote: Hi, 2. Assume I have a big graph in the REST server, what is the best way to remove the whole graph? Of course deleting each node and its relationships and its index is not convenient. Via Gremlin Plugin, you can call g.clear(). HTH, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best wishes, Linan Wang Architect, Programmer, PhD ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] REST, Transactions and Uniqueness
Peter,
I feel uniqueness has been a recurring theme in neo4j applications,
especially when it's used heavily on algorithms traversing existing
data. it would be great if it's supported in kernel level:
interface NodeUniquenessConstraint
{
public Node getNode();
public void setupNode(Node newNode);
}
public Node getOrCreateNode(NodeUniquenessConstraint constraint)
{
// Preparation, acquires lock, etc.
Node n = constraint.getNode();
if(n == null)
{
n = createNode();
constraint.setupNode(n);
}
...
return n;
}
or, there is something similar already implemented?
On Tue, Sep 27, 2011 at 9:38 PM, Peter Neubauer
peter.neuba...@neotechnology.com wrote:
Guys,
Maps are now supported as parameters, look at the Gremlin plugin för
reference in the docs. Will add that for parameters to the cypher plugin
too.
Thanks for chipping in!
/peter
Sent from my phone.
On Sep 27, 2011 8:12 PM, Tony Wooster twoos...@gmail.com wrote:
Hi Linan,
That's essentially what I implemented, but the logic just became that
much more tortured when going over REST. Like I said, less of a Java
programmer. The implementation I came up with on the REST side (hacky
though it may be) was this:
@Description( An extension to help maintain unique relationships )
public class IndexTester extends ServerPlugin
{
@Name( error_if_in_node_index )
@Description( Will return a 4xx error if a key/value pair is found in
+
a given index. Also errors if the index doesn't
exist.)
@PluginTarget( GraphDatabaseService.class )
public Boolean errorIfInNodeIndex(
@Source GraphDatabaseService graphDb,
@Description( Name of the index to earch. )
@Parameter( name = indexName ) String indexName,
@Description( Name of key to search. )
@Parameter( name = key ) String key,
@Description( Value to search for. )
@Parameter( name = value ) String value )
throws BadInputException
{
if ( !graphDb.index().existsForNodes( indexName ) )
throw new BadInputException(Index doesn't exist, new
NotFoundException());
IndexNode index = graphDb.index().forNodes( indexName );
if (index.get(key, value).size() 0)
throw new BadInputException(Key/value pair found in index);
return null;
}
}
I'm still not entirely certain that this is the appropriate way to go;
probably a better solution would be a more general add node with
unique, indexed fields command that's slightly more functional than
this batch-operation-quirks based hack. As an aside -- does anyone
know when/if lists of maps for parameters will be implemented for REST
plugins?
Thanks for the response!
-T
On Thu, Sep 22, 2011 at 4:57 PM, Linan Wang tali.w...@gmail.com wrote:
Hi,
i had the issue few days ago and thanks to McKinley I got a workable
solution. i think the best way to do is through unmanaged extension.
the overhead of multiple REST calls could make the matter more
complex.
here is part of my ObjectFactory class. in my situation it's an
external id needs to be uniq. feel free to correct my codes :) the
performance is not ideal though. on my imac I got around 50 insertions
per sec. the bottle neck is not memory.
public T get(long externalId)
{
// try asynchronized read first;
IndexNode idx = getDefaultNodeIndex();
IndexHitsNode h = idx.get(IDX_KEY_EXTERNAL_ID,
externalId);
Node n = h.getSingle();
h.close();
if(n != null)
return wrap(n);
// if not found, try synchronized version;
return null;
}
public T getOrCreate(long externalId)
{
T ret = get( externalId );
if(ret != null)
return ret;
// if not found, try synchronized version;
return synchronizedGetOrCreate(externalId);
}
private synchronized T synchronizedGetOrCreate(long externalId)
{
// Just in case!
T ret = get( externalId );
if(ret != null)
return ret;
IndexNode idx = getDefaultNodeIndex();
Node n = null;
Transaction tx = db.beginTx();
try{
n = db.createNode();
// set property
n.setProperty(AbstractObject.EXTERNAL_ID_KEY,
externalId);
// add to default index;
idx.add(n, IDX_KEY_EXTERNAL_ID, externalId);
tx.success();
}catch(Exception e){
tx.failure();
}finally{
tx.finish
Re: [Neo4j] REST, Transactions and Uniqueness
peter,
a quick implementation is submitted. pull request sent. my naming
ability is probably not the best part. see if the codes make sense.
thanks.
On Wed, Sep 28, 2011 at 10:10 PM, Peter Neubauer
peter.neuba...@neotechnology.com wrote:
Linan,
It's high prio in the backlog for 1.6, so this WILL be taken care of. I
believe there is also an issue on this on Github? If not, please raise one
to track progress for the community. Thanks!
/peter
Sent from my phone.
On Sep 28, 2011 10:02 PM, Linan Wang tali.w...@gmail.com wrote:
Peter,
I feel uniqueness has been a recurring theme in neo4j applications,
especially when it's used heavily on algorithms traversing existing
data. it would be great if it's supported in kernel level:
interface NodeUniquenessConstraint
{
public Node getNode();
public void setupNode(Node newNode);
}
public Node getOrCreateNode(NodeUniquenessConstraint constraint)
{
// Preparation, acquires lock, etc.
Node n = constraint.getNode();
if(n == null)
{
n = createNode();
constraint.setupNode(n);
}
...
return n;
}
or, there is something similar already implemented?
On Tue, Sep 27, 2011 at 9:38 PM, Peter Neubauer
peter.neuba...@neotechnology.com wrote:
Guys,
Maps are now supported as parameters, look at the Gremlin plugin för
reference in the docs. Will add that for parameters to the cypher plugin
too.
Thanks for chipping in!
/peter
Sent from my phone.
On Sep 27, 2011 8:12 PM, Tony Wooster twoos...@gmail.com wrote:
Hi Linan,
That's essentially what I implemented, but the logic just became that
much more tortured when going over REST. Like I said, less of a Java
programmer. The implementation I came up with on the REST side (hacky
though it may be) was this:
@Description( An extension to help maintain unique relationships )
public class IndexTester extends ServerPlugin
{
@Name( error_if_in_node_index )
@Description( Will return a 4xx error if a key/value pair is found
in
+
a given index. Also errors if the index doesn't
exist.)
@PluginTarget( GraphDatabaseService.class )
public Boolean errorIfInNodeIndex(
@Source GraphDatabaseService graphDb,
@Description( Name of the index to earch. )
@Parameter( name = indexName ) String indexName,
@Description( Name of key to search. )
@Parameter( name = key ) String key,
@Description( Value to search for. )
@Parameter( name = value ) String value )
throws BadInputException
{
if ( !graphDb.index().existsForNodes( indexName ) )
throw new BadInputException(Index doesn't exist, new
NotFoundException());
IndexNode index = graphDb.index().forNodes( indexName );
if (index.get(key, value).size() 0)
throw new BadInputException(Key/value pair found in
index);
return null;
}
}
I'm still not entirely certain that this is the appropriate way to go;
probably a better solution would be a more general add node with
unique, indexed fields command that's slightly more functional than
this batch-operation-quirks based hack. As an aside -- does anyone
know when/if lists of maps for parameters will be implemented for REST
plugins?
Thanks for the response!
-T
On Thu, Sep 22, 2011 at 4:57 PM, Linan Wang tali.w...@gmail.com wrote:
Hi,
i had the issue few days ago and thanks to McKinley I got a workable
solution. i think the best way to do is through unmanaged extension.
the overhead of multiple REST calls could make the matter more
complex.
here is part of my ObjectFactory class. in my situation it's an
external id needs to be uniq. feel free to correct my codes :) the
performance is not ideal though. on my imac I got around 50 insertions
per sec. the bottle neck is not memory.
public T get(long externalId)
{
// try asynchronized read first;
IndexNode idx = getDefaultNodeIndex();
IndexHitsNode h = idx.get(IDX_KEY_EXTERNAL_ID,
externalId);
Node n = h.getSingle();
h.close();
if(n != null)
return wrap(n);
// if not found, try synchronized version;
return null;
}
public T getOrCreate(long externalId)
{
T ret = get( externalId );
if(ret != null)
return ret;
// if not found, try synchronized version;
return synchronizedGetOrCreate(externalId);
}
private synchronized T synchronizedGetOrCreate(long externalId)
{
// Just in case!
T ret = get( externalId );
if(ret != null)
return ret;
IndexNode idx = getDefaultNodeIndex();
Node n = null
Re: [Neo4j] REST, Transactions and Uniqueness
. Add a User node
5. Relate it back to the UserRef node
5. Add it to the index
6. Release lock on UserRef supernode by re-adding __WRITE_LOCK__ property
7. Finish HTTP request, done
This seems to work, but, again, are there any blind-spots that I'm unaware
of? How about if this goes to a HA cluster?
Finally, somewhat related, are some concerns with the batch API
back-reference capability. This appears to manifest itself as a blind
string-replace of '{[id]}' in provided fields. This _seems_ like it could
have some security/annoying bug concerns relating to user-provided data
(local portion of email address includes the substring '{1}', for example,
which is valid per the email spec). I currently don't see any way around
this except to restrict user input. Any thoughts?
Anyway, thanks for any comments and responses!
-Tony Wooster
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Re: [Neo4j] Creating a graph database with BatchInserter and getting the node degree of every node
Hi stephan, I mis-calculated the size of relationshipstore.db. i thought it was around 8G instead of 85G. the only option left i think is to build index. something like this: idx = db.index().forNode(knows); idx.add(thisguy, knows, thatguy.getId()); idx.add(thatguy, known_by, thisguy.getId()); the benefit is that when querying, the return size is pre-calculated so it would save some iteration time. the problem is the index files size, should around 85G. On Wed, Sep 21, 2011 at 11:44 AM, st3ven st3...@web.de wrote: Hi Linan, I just tried it with the outgoing relationships, but unfortunately that didn't speed things up. The size of my db is around 140GB and so it is not possible for me to dumb the full directory into a ramfs. My files on the hard disk have the following size: neostore.nodestore.db = 31MB neostore.relationshipstore.db = 85GB neostore.propertystore.db = 65GB neostore.propertystore.db.strings = 180MB Is there maybe a chance of reducing the size of my database? Cheers, Stephan -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Creating-a-graph-database-with-BatchInserter-and-getting-the-node-degree-of-every-node-tp3351599p3355074.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Error in performance docs - Stack Size
k/m/g all work. just tried on 1.6. On Thu, Sep 22, 2011 at 2:22 AM, Romiko Derbynew romiko.derby...@readify.net wrote: Sorry, clicked wrong button: http://wiki.neo4j.org/content/Configuration_Settings The stack size is set by specifying the -Xss???m parameter to hotspot, where ??? is the stack size in megabytes. As far as I am aware, according to this document: http://www.caucho.com/resin-3.0/performance/jvm-tuning.xtp#stack-size The stack size in in kilobytes, which kind a makes sense. -Xss determines the size of the stack: -Xss1024k Please confirm? From: Romiko Derbynew Sent: Thursday, 22 September 2011 11:19 AM To: 'user@lists.neo4j.org' Subject: Error in performance docs - Stack Size Hi Guys, I think there is an error in the performance docs. I am currently tuning the stack size as we use multiple threads, however, I see this in the docs: ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Creating a graph database with BatchInserter and getting the node degree of every node
hi Stephan,
have you set the -Xms, -XX:+UseNUMA, and -XX:+UseConcMarkSweepGC? they
could speedup the process significantly.
also, if you like, the jrockit is fast and free now. give it a try.
btw, which file system you are using? have you turned off atime?
On Tue, Sep 20, 2011 at 12:00 PM, st3ven st3...@web.de wrote:
Peter,
the import of the data into the graph database is not the main problem for
me.
The lookup of nodes from the index is fast enough for me.
To create the database it took me nearly half a day.
My main problem here is getting the node degree of every node.
As I already said I am using this code to get the node degree of every node:
for (Node node : db.getAllNodes()) {
counter = 0;
if (node.getId() 0) {
for (Relationship rel :
node.getRelationships()) {
counter++;
}
System.out.println(node.getProperty(name).toString() + :
+ counter);
}
}
After 3 days I only got the node degree of 8 nodes and I want to
optimize my traversal here, cause this is very slow.
What can I do to make this faster or do I have to change my code for getting
the node degree?
I only posted my import code because I thought I could maybe optimize there
something for this traversal.
Thank you very much for your help!
Cheers,
Stephan
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Re: [Neo4j] Creating a graph database with BatchInserter and getting the node degree of every node
hi stephan i'm wondering if any difference if you could specify the relationship when counting degrees: RelationshipType knows = DynamicRelationshipType.withName(KNOWS); Iterable rels = node.getRelationship(knows); count = com.google.common.collect.Iterables.size(rels); besides, do you know where is the bottle neck is, the node iteration or relationship retrieval? On Tue, Sep 20, 2011 at 1:38 PM, st3ven st3...@web.de wrote: Hi, I already tried these java parameters, but that didn't really speedup the process and i already turned atime off. As Java parameters I am using right now -d64 -server -Xms7G -Xmx14G -XX:+UseParallelGC -XX:+UseNUMA What I've also noticed is, that reading from the database is really slow on my hard disk. It just reads 1mb/s and sometimes 8mb/s, but that is really slow. My hard disk can normally read and copy files much faster. Also very strange is, that the workload of the hard disk is around 99% with reading 1mb/s. My OS is Ubuntu Linux x64 and my file system is ext4. On the neo4j Wiki I found some performance guides, but these didn't really help. Do you know what I can do else? Perfomance Guides: http://wiki.neo4j.org/content/Linux_Performance_Guide http://wiki.neo4j.org/content/Linux_Performance_Guide http://wiki.neo4j.org/content/Configuration_Settings http://wiki.neo4j.org/content/Configuration_Settings I also added a configurtion file, but it seems that my Java program doesn't use all of the Ram. Thanks for your help! Cheers, Stephan -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Creating-a-graph-database-with-BatchInserter-and-getting-the-node-degree-of-every-node-tp3351599p3351881.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Creating a graph database with BatchInserter and getting the node degree of every node
-database-with-BatchInserter-and-getting-the-node-degree-of-every-node-tp3351599p3352415.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Creating a graph database with BatchInserter and getting the node degree of every node
Stephan, what's the size of your db? if it's under 10G, how about just dump the full directory into to a ramfs. leave 1G to jvm and it'll do heavy io on the ramfs. i think it's a simple solution and could yield interesting result. please let me know the result if you tried. thanks On Tue, Sep 20, 2011 at 5:41 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Steven, the index is built into the DB, so you can use something like http://docs.neo4j.org/chunked/snapshot/tutorials-java-embedded-index.html to index all your nodes into Lucene (in one index, the node as key, the number of relationships as numeric value when creating them). When reading, you would simply request all keys from the index and iterate over them. I am not terribly sure how much fast it is, but given that you are just loading up documents, Lucene should be reasonably fast. Let us know if that works out! Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Tue, Sep 20, 2011 at 6:01 PM, st3ven st3...@web.de wrote: Hello Peter, it's a pity that neo4j doesn't support full graph-scans. Is there maybe a possibility to cache more relationships to speed things up a little bit. I recognized that only the iteration over the relationships is taking hours. The time to get all relationships of one node is quite fast. I think I could try your second solution: - Store the relationships as a property in an Index (e.g. Lucene) and as the index for all entries. Thus, you are using an index for what it is good at - global operations over all documents. But I didn't understood it correctly. Do you mean an Index which stores the ID of a relationship and creating such an Index for every node? Could you maybe give me a code example for that? That would be very kind of you. The first solution is not really realizable, because I don't know the number of relationships of every node. I would have to count the relationships before the insertion and that would make my database useless for the node degree query. Thank you very much for your help! Cheers, Stephan -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Creating-a-graph-database-with-BatchInserter-and-getting-the-node-degree-of-every-node-tp3351599p3352509.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
[Neo4j] lock or not?
hi all, I have implemented a function UserFactory.get_or_create_with_external_id(long external_id). the function basically search the index, see if a node already created and has the property external_id equals to external_id. if there is such a node, return, if not, create one, assign property and index it. this function will be called inside of transactions, from unmanaged extensions. so it's multi-threaded scenario. my question is if i need to mark the function synchronized. my guess is true, and i feel it'll hurt performance badly. if my guess is wrong, why? thanks -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] lock or not?
McKinley Thank you very much for the detailed explanation. however, I don't get the part about only one JVM will access database. neo4j doesn't support multiple JVMs has write access to the same db, right? On Wed, Sep 14, 2011 at 9:14 PM, McKinley mckinley1...@gmail.com wrote: If a second thread reads that there is no node with external_id 123 in between the time that a first thread finds no node and elects to create it, you will get 2 nodes with external_id 123. So yes, you need to introduce a lock and synchronize. You can create read locks in the graph database but you probably will not need to do that. In your case you are reading from an index and I am not sure what locks are available for indexes. If you are running an embedded database and you can be sure that only your one JVM will access the database then you can just lock in the Java thread/object space and elect that other threads must wait to read if the node exists until the first thread has created it. If you need to communicate concurrency via the database, you will have to do all the same locking in the Java space and add a read lock on some control node in Neo4j. If you want to create a read lock on a node you can do the following: lockManager = graphDb.getConfig().getLockManager(); lockManager.getReadLock(someNode); ... lockManager.releaseReadLock(someNode, null); Threading and synchronization in Java will perform great. Depending on your model, most of the time your node will exist and two or more threads will just queue up and get the same reference. That waiting is inefficient by nature, but if your business rules require it then you have to do it. Cheers, McKinley On Wed, Sep 14, 2011 at 12:45 PM, Linan Wang tali.w...@gmail.com wrote: hi all, I have implemented a function UserFactory.get_or_create_with_external_id(long external_id). the function basically search the index, see if a node already created and has the property external_id equals to external_id. if there is such a node, return, if not, create one, assign property and index it. this function will be called inside of transactions, from unmanaged extensions. so it's multi-threaded scenario. my question is if i need to mark the function synchronized. my guess is true, and i feel it'll hurt performance badly. if my guess is wrong, why? thanks -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] lock or not?
Got it. i really appreciate your help. On Wed, Sep 14, 2011 at 11:14 PM, McKinley mckinley1...@gmail.com wrote: I mean that if you are not running the REST server or high availability then you can assume that even if you only put the read lock in the Java thread/object world, the database will not change. No other process exists that could change it. You do not need to bother with a read lock in the database. Cheers, McKinley On Wed, Sep 14, 2011 at 3:07 PM, Linan Wang tali.w...@gmail.com wrote: McKinley Thank you very much for the detailed explanation. however, I don't get the part about only one JVM will access database. neo4j doesn't support multiple JVMs has write access to the same db, right? On Wed, Sep 14, 2011 at 9:14 PM, McKinley mckinley1...@gmail.com wrote: If a second thread reads that there is no node with external_id 123 in between the time that a first thread finds no node and elects to create it, you will get 2 nodes with external_id 123. So yes, you need to introduce a lock and synchronize. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Unmanaged Extensions
Peter, thanks. it's here: https://github.com/wangii/test2 must be something in the doc i didn't notice, even though i've read 5 times! On Mon, Sep 12, 2011 at 3:06 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Linan, got a small project to build this for so I can test it out? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Mon, Sep 12, 2011 at 4:04 PM, wangii tali.w...@gmail.com wrote: Got the same ResourceConfig problem: The ResourceConfig instance does not contain any root resource. tried to put jar file into /lib, /plugins, modified neo4j-server.properties file. anything I missed here? thanks -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Unmanaged-Extensions-tp2660066p3329694.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Unmanaged Extensions
sure. it's here: https://github.com/wangii/test2/blob/master/test2.jar On Mon, Sep 12, 2011 at 3:56 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Thanks Linan, Could you also put up the jar you deploy so I can test it, since you seem to rely on Eclipse building which I can't recreate? /peter Sent from my phone. On Sep 12, 2011 4:14 PM, Linan Wang tali.w...@gmail.com wrote: Peter, thanks. it's here: https://github.com/wangii/test2 must be something in the doc i didn't notice, even though i've read 5 times! On Mon, Sep 12, 2011 at 3:06 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Linan, got a small project to build this for so I can test it out? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Mon, Sep 12, 2011 at 4:04 PM, wangii tali.w...@gmail.com wrote: Got the same ResourceConfig problem: The ResourceConfig instance does not contain any root resource. tried to put jar file into /lib, /plugins, modified neo4j-server.properties file. anything I missed here? thanks -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Unmanaged-Extensions-tp2660066p3329694.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Unmanaged Extensions
yes, i did it. i package it into jar file just to show that i've modified the file. will it related to the 64 jvm shipped in osx lion? i'm reading the source codes... On Mon, Sep 12, 2011 at 6:55 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Linan, you need to change the neo4j-server.properties in the Neo4j Server conf/ directory where you want to deploy your extension in order to get this picked up, not packaging it with the extension jar. Could you please try that? See also http://docs.neo4j.org/chunked/snapshot/server-unmanaged-extensions.html for details. Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Mon, Sep 12, 2011 at 5:01 PM, Linan Wang tali.w...@gmail.com wrote: sure. it's here: https://github.com/wangii/test2/blob/master/test2.jar On Mon, Sep 12, 2011 at 3:56 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Thanks Linan, Could you also put up the jar you deploy so I can test it, since you seem to rely on Eclipse building which I can't recreate? /peter Sent from my phone. On Sep 12, 2011 4:14 PM, Linan Wang tali.w...@gmail.com wrote: Peter, thanks. it's here: https://github.com/wangii/test2 must be something in the doc i didn't notice, even though i've read 5 times! On Mon, Sep 12, 2011 at 3:06 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Linan, got a small project to build this for so I can test it out? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Mon, Sep 12, 2011 at 4:04 PM, wangii tali.w...@gmail.com wrote: Got the same ResourceConfig problem: The ResourceConfig instance does not contain any root resource. tried to put jar file into /lib, /plugins, modified neo4j-server.properties file. anything I missed here? thanks -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Unmanaged-Extensions-tp2660066p3329694.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Unmanaged Extensions
what i've found: PluginInitializer (https://github.com/neo4j/community/blob/master/server/src/main/java/org/neo4j/server/modules/PluginInitializer.java) 1, probably has a spell mistake: intitializePackages, maybe initializePackages? 2, i don't understand how pluginlifecycle is related to thirdparty jaxrs On Mon, Sep 12, 2011 at 6:58 PM, Linan Wang tali.w...@gmail.com wrote: yes, i did it. i package it into jar file just to show that i've modified the file. will it related to the 64 jvm shipped in osx lion? i'm reading the source codes... On Mon, Sep 12, 2011 at 6:55 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Linan, you need to change the neo4j-server.properties in the Neo4j Server conf/ directory where you want to deploy your extension in order to get this picked up, not packaging it with the extension jar. Could you please try that? See also http://docs.neo4j.org/chunked/snapshot/server-unmanaged-extensions.html for details. Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Mon, Sep 12, 2011 at 5:01 PM, Linan Wang tali.w...@gmail.com wrote: sure. it's here: https://github.com/wangii/test2/blob/master/test2.jar On Mon, Sep 12, 2011 at 3:56 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Thanks Linan, Could you also put up the jar you deploy so I can test it, since you seem to rely on Eclipse building which I can't recreate? /peter Sent from my phone. On Sep 12, 2011 4:14 PM, Linan Wang tali.w...@gmail.com wrote: Peter, thanks. it's here: https://github.com/wangii/test2 must be something in the doc i didn't notice, even though i've read 5 times! On Mon, Sep 12, 2011 at 3:06 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Linan, got a small project to build this for so I can test it out? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Mon, Sep 12, 2011 at 4:04 PM, wangii tali.w...@gmail.com wrote: Got the same ResourceConfig problem: The ResourceConfig instance does not contain any root resource. tried to put jar file into /lib, /plugins, modified neo4j-server.properties file. anything I missed here? thanks -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Unmanaged-Extensions-tp2660066p3329694.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Unmanaged Extensions
Yes, it works! thank you very much! On Mon, Sep 12, 2011 at 8:22 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Thanks Linan for the find! I corrected the spelling of the function. Also, JAXRS is not related to Server Plugin lifecycle - it is a raw JAXRS registration into the webserver. For your test jar, I got things working when checking in the export dialog to include directory information, see the attached picture. Then, I can set org.neo4j.server.thirdparty_jaxrs_classes=org.neo4j.examples=/hello in neo4j-server/properties and get with curl http://localhost:7474/hello/0 Hello World, nodeId=0 Does that work for you? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Mon, Sep 12, 2011 at 8:12 PM, Linan Wang tali.w...@gmail.com wrote: what i've found: PluginInitializer (https://github.com/neo4j/community/blob/master/server/src/main/java/org/neo4j/server/modules/PluginInitializer.java) 1, probably has a spell mistake: intitializePackages, maybe initializePackages? 2, i don't understand how pluginlifecycle is related to thirdparty jaxrs On Mon, Sep 12, 2011 at 6:58 PM, Linan Wang tali.w...@gmail.com wrote: yes, i did it. i package it into jar file just to show that i've modified the file. will it related to the 64 jvm shipped in osx lion? i'm reading the source codes... On Mon, Sep 12, 2011 at 6:55 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Linan, you need to change the neo4j-server.properties in the Neo4j Server conf/ directory where you want to deploy your extension in order to get this picked up, not packaging it with the extension jar. Could you please try that? See also http://docs.neo4j.org/chunked/snapshot/server-unmanaged-extensions.html for details. Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Mon, Sep 12, 2011 at 5:01 PM, Linan Wang tali.w...@gmail.com wrote: sure. it's here: https://github.com/wangii/test2/blob/master/test2.jar On Mon, Sep 12, 2011 at 3:56 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Thanks Linan, Could you also put up the jar you deploy so I can test it, since you seem to rely on Eclipse building which I can't recreate? /peter Sent from my phone. On Sep 12, 2011 4:14 PM, Linan Wang tali.w...@gmail.com wrote: Peter, thanks. it's here: https://github.com/wangii/test2 must be something in the doc i didn't notice, even though i've read 5 times! On Mon, Sep 12, 2011 at 3:06 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Linan, got a small project to build this for so I can test it out? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Mon, Sep 12, 2011 at 4:04 PM, wangii tali.w...@gmail.com wrote: Got the same ResourceConfig problem: The ResourceConfig instance does not contain any root resource. tried to put jar file into /lib, /plugins, modified neo4j-server.properties file. anything I missed here? thanks -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Unmanaged-Extensions-tp2660066p3329694.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org
Re: [Neo4j] performance guide
Andreas, thanks. can't wait for your result. one correction on my list: Retrieve a certain types of relationships of a node should be faster than retrieve all. i mis-read the source code in NodeImpl.java, in which private volatile RelIdArray[] relationships is an array of array. the updated list: 1, Read id of a node/relationship. 2, Read property value of a node/relationship. 3, Set property value of a node/relationship. 4, Retrieve a node/relationship by id. 5, Create a new node/relationship. 6, Retrieve a node by external id from node index. 7, Retrieve a certain subset of relationships of a node from RelationshipIndex. 8, Retrieve all relationships of a node. 9, Retrieve a certain types of relationships of a node. 10, Add a node to index. 11, Add a relationship to index. could anyone confirm that to iterate relationships of a node, Node.getRelationships() is faster than using RelationshipIndex.get(KEY, VAL, node, null)? thanks On Sat, Sep 10, 2011 at 1:46 AM, Andreas Kollegger andreas.kolleg...@neotechnology.com wrote: Hi Linan, These are good questions. I am currently following a similar approach to characterizing the performance of basic graph operations, and then also simple graph algorithms on various shapes of graphs. My initial investigation is on small graphs on my laptop, but this weekend I'm testing large graphs on Amazon instances (large, as in 500 million nodes). I'll post the summary of my findings from this weekend, then continue to elaborate on the operations and different server configurations. Best, Andreas On Sep 9, 2011, at 4:29 PM, Linan Wang wrote: hi, I once read a blog about how long it take for computation operations such as read from L1 cache, RAM access, send packet from usa to eu, etc. having a rough idea of the relative cost of major computation operations, we have better control. for example, in my project i also use property to store a cityid apart from create a relationship between user to city, because if reading an int property is 10x faster than getSingleRelationship + relationship.getEndNode + cityNode.getId. I'm wondering if could having similar list for neo4j operations. I understand some operations could be faster than another depending on different conditions. but let's only focus on basic read/write operations. below is my guess, from fastest to slowest, feel free to correct me and add more. 1, Read id of a node/relationship. 2, Read property value of a node/relationship. 3, Set property value of a node/relationship. 4, Retrieve a node/relationship by id. 5, Create a new node/relationship. 6, Retrieve a node by external id from node index. 7, Retrieve all relationships of a node. 8, Retrieve a certain subset of relationships of a node from RelationshipIndex. 9, Retrieve a certain types of relationships of a node. 10, Add a node to index. 11, Add a relationship to index. -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] regarding supernode
how about i put the codes onto github and you guys can comment and modify it. then include the project as a sample? On Fri, Sep 9, 2011 at 8:58 AM, Peter Neubauer pe...@neubauer.se wrote: Linan, I think your example would be great for doing a JUnit test showing this. Niels, could you do that, plz? In that case, I can add a graph and exaplanations to it. /peter On Thu, Sep 8, 2011 at 11:25 PM, Linan Wang tali.w...@gmail.com wrote: On Wed, Sep 7, 2011 at 5:21 PM, Linan Wang tali.w...@gmail.com wrote: hi, I don't quite understand RelationshipIndex and RelationshipExpander. say I have a supernode city (beijing), it has 10 m users links to through relationship LIVES_IN. so how should I index? should be something like: RelationshipIndex idx = db.index().forRelationships(CITY_LIVES_IN); idx.add(rel, LIVES_IN, Beijing); if so, what's the advantage over this? IndexNode idx = db.index().forNodes(CITY_LIVES_IN); idx.add(user, LIVES_IN, beijing); (I read source code of LuceneIndex.java, found out that the implementation of the add method is shared between Indexnode and RelationshipIndex.) ok, i answer my own question: RelationshipIndex has the function query which takes startNode and endNode as extra parameters. so if traverse only depth 1, it could be faster than using Traverser. am i right here? (please say yes!) then the question is how to take advantage of it for more than 1? about RelationshipExpander. i don't see how RelationshipIndex could help combining with RelationshipExpander, when use GraphAlgoFactory.shortestPath(RelationshipExpander expander, int maxDepth)? thanks for help! -- Best regards Linan Wang -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] chain TraversalDescription?
Actually i'm fine with nesting multiple traversers to solve the
problem if deep inside gremlin, evaluator and fluentPipeline are just
nice constructs over the same solution. is it correct?
thanks
On Fri, Sep 9, 2011 at 7:03 PM, Linan Wang tali.w...@gmail.com wrote:
Thanks! I really appreciate. i'll have a deeper look at the
FluentPipeline and Gremlin options later.
Regarding using Evaluator in
https://github.com/neo4j/community/blob/master/embedded-examples/src/test/java/org/neo4j/examples/orderedpath/OrderedPathTest.java
my question:
When the Evaluator.evaluate is called, the last node in the path is
already retrieved, right? using the example, at depth 1, all my dogs
and books i wrote have been retrieved, what the evaluator does is to
decide not to continue from the, and exclude it in the return. am i
right? any way to prevent from retrieving them at all? imagine i've
written 10,000 books and have 1m dogs, visiting these nodes would be
waste of time.
On Fri, Sep 9, 2011 at 4:12 PM, Peter Neubauer
peter.neuba...@neotechnology.com wrote:
That's right!
Looking all forward to that!
Cheers,
/peter neubauer
GTalk: neubauer.peter
Skype peter.neubauer
Phone +46 704 106975
LinkedIn http://www.linkedin.com/in/neubauer
Twitter http://twitter.com/peterneubauer
http://www.neo4j.org - Your high performance graph database.
http://startupbootcamp.org/ - Öresund - Innovation happens HERE.
http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party.
On Fri, Sep 9, 2011 at 5:10 PM, Marko Rodriguez okramma...@gmail.com wrote:
Hey,
Hi Linan,
http://docs.neo4j.org/chunked/snapshot/tutorials-java-embedded-traversal.html#_new_traversal_framework
has an example of an ordered path, does that help? The code for it is
at
https://github.com/neo4j/community/blob/master/embedded-examples/src/test/java/org/neo4j/examples/orderedpath/OrderedPathTest.java
Also, Gremlin, as Marko states, is applicable here.
One more point to this. The next release of the Pipes comes with
FluentPipeline which will allow you to, in native Java, do this:
PipeVertex,String pipe = new
FluentPipeline(graph.getVertex(1)).out(read).in(wrote).uniqueObject().out(pet).property(name);
while(pipe.hasNext()) {
String petName = pipe.next();
}
In this way, you can effect the same Gremlin-esque behavior, but in pure
Java.
This is planned for a September 21st released and, if all goes well, will
be in the next release of Neo4j.
Take care,
Marko.
http://markorodriguez.com
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[Neo4j] performance guide
hi, I once read a blog about how long it take for computation operations such as read from L1 cache, RAM access, send packet from usa to eu, etc. having a rough idea of the relative cost of major computation operations, we have better control. for example, in my project i also use property to store a cityid apart from create a relationship between user to city, because if reading an int property is 10x faster than getSingleRelationship + relationship.getEndNode + cityNode.getId. I'm wondering if could having similar list for neo4j operations. I understand some operations could be faster than another depending on different conditions. but let's only focus on basic read/write operations. below is my guess, from fastest to slowest, feel free to correct me and add more. 1, Read id of a node/relationship. 2, Read property value of a node/relationship. 3, Set property value of a node/relationship. 4, Retrieve a node/relationship by id. 5, Create a new node/relationship. 6, Retrieve a node by external id from node index. 7, Retrieve all relationships of a node. 8, Retrieve a certain subset of relationships of a node from RelationshipIndex. 9, Retrieve a certain types of relationships of a node. 10, Add a node to index. 11, Add a relationship to index. -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Blocking access to the Neo4j web admin interface
since neo4j just uses jetty, i think the simple solution would be add option in neo4j shell script: -Djetty.host=127.0.0.1 to make it only listen to local request. then use ssh tunnel to expose service to designated machines. On Thu, Sep 8, 2011 at 2:18 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Hi there, you can block access to it by blocking the access to the URL (localhost:.../webadmin) and even /db/manage. That requires probably to set up apache and mod_proxy in front of the Neo4j server, but I think that is a good idea in production scenarios anyway. http://docs.neo4j.org/chunked/snapshot/operations-security.html Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Thu, Sep 8, 2011 at 3:08 PM, carze ca...@som.umaryland.edu wrote: I'm making use of the Neo4j REST API to power a website and was wondering if there was any way to block access to the web admin interface. Currently the DB is in read-only mode but the web admin panel is accessibly by anyone who can stumble upon the URL. -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Blocking-access-to-the-Neo4j-web-admin-interface-tp3319626p3319626.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Blocking access to the Neo4j web admin interface
tested the idea, it doesn't work. so i made simple changes to the server code and diff is attached. to change the binding ip of the webserver: add following line to conf/neo4j-server.properties: org.neo4j.server.webserver.address=127.0.0.1 On Thu, Sep 8, 2011 at 2:55 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: That sounds good. Could you try it and report back? Would love to add it to the manual and as a setting. Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Thu, Sep 8, 2011 at 3:34 PM, Linan Wang tali.w...@gmail.com wrote: since neo4j just uses jetty, i think the simple solution would be add option in neo4j shell script: -Djetty.host=127.0.0.1 to make it only listen to local request. then use ssh tunnel to expose service to designated machines. On Thu, Sep 8, 2011 at 2:18 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Hi there, you can block access to it by blocking the access to the URL (localhost:.../webadmin) and even /db/manage. That requires probably to set up apache and mod_proxy in front of the Neo4j server, but I think that is a good idea in production scenarios anyway. http://docs.neo4j.org/chunked/snapshot/operations-security.html Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Thu, Sep 8, 2011 at 3:08 PM, carze ca...@som.umaryland.edu wrote: I'm making use of the Neo4j REST API to power a website and was wondering if there was any way to block access to the web admin interface. Currently the DB is in read-only mode but the web admin panel is accessibly by anyone who can stumble upon the URL. -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Blocking-access-to-the-Neo4j-web-admin-interface-tp3319626p3319626.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] regarding supernode
On Wed, Sep 7, 2011 at 5:21 PM, Linan Wang tali.w...@gmail.com wrote: hi, I don't quite understand RelationshipIndex and RelationshipExpander. say I have a supernode city (beijing), it has 10 m users links to through relationship LIVES_IN. so how should I index? should be something like: RelationshipIndex idx = db.index().forRelationships(CITY_LIVES_IN); idx.add(rel, LIVES_IN, Beijing); if so, what's the advantage over this? IndexNode idx = db.index().forNodes(CITY_LIVES_IN); idx.add(user, LIVES_IN, beijing); (I read source code of LuceneIndex.java, found out that the implementation of the add method is shared between Indexnode and RelationshipIndex.) ok, i answer my own question: RelationshipIndex has the function query which takes startNode and endNode as extra parameters. so if traverse only depth 1, it could be faster than using Traverser. am i right here? (please say yes!) then the question is how to take advantage of it for more than 1? about RelationshipExpander. i don't see how RelationshipIndex could help combining with RelationshipExpander, when use GraphAlgoFactory.shortestPath(RelationshipExpander expander, int maxDepth)? thanks for help! -- Best regards Linan Wang -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Blocking access to the Neo4j web admin interface
done. https://github.com/neo4j/community/pull/16 On Thu, Sep 8, 2011 at 11:21 PM, Michael Hunger michael.hun...@neotechnology.com wrote: Linan, your diff didn't make it could you just issue an pull request for that. And Peter should get you sign a CLA btw. Cheers Michael Am 08.09.2011 um 18:33 schrieb Linan Wang: tested the idea, it doesn't work. so i made simple changes to the server code and diff is attached. to change the binding ip of the webserver: add following line to conf/neo4j-server.properties: org.neo4j.server.webserver.address=127.0.0.1 On Thu, Sep 8, 2011 at 2:55 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: That sounds good. Could you try it and report back? Would love to add it to the manual and as a setting. Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Thu, Sep 8, 2011 at 3:34 PM, Linan Wang tali.w...@gmail.com wrote: since neo4j just uses jetty, i think the simple solution would be add option in neo4j shell script: -Djetty.host=127.0.0.1 to make it only listen to local request. then use ssh tunnel to expose service to designated machines. On Thu, Sep 8, 2011 at 2:18 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Hi there, you can block access to it by blocking the access to the URL (localhost:.../webadmin) and even /db/manage. That requires probably to set up apache and mod_proxy in front of the Neo4j server, but I think that is a good idea in production scenarios anyway. http://docs.neo4j.org/chunked/snapshot/operations-security.html Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/ - Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Thu, Sep 8, 2011 at 3:08 PM, carze ca...@som.umaryland.edu wrote: I'm making use of the Neo4j REST API to power a website and was wondering if there was any way to block access to the web admin interface. Currently the DB is in read-only mode but the web admin panel is accessibly by anyone who can stumble upon the URL. -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Blocking-access-to-the-Neo4j-web-admin-interface-tp3319626p3319626.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Index entry removal after relationship deletion
as far as i know, no. you need to do it yourself. hint: http://docs.neo4j.org/chunked/1.4.1/indexing-update.html On Wed, Sep 7, 2011 at 1:25 AM, Nuo Yan yan@gmail.com wrote: Hey guys, When a relationship gets deleted, will it be removed from the index automatically? My test shows yes, but I want to be absolutely certain. For example, a relationship :foo exists between node A and B and it's indexed on the foo_rels index with key node_a's id and value node_b's id. When I delete this relationship, do I also have to manually remove it from the index (i.e. a DELETE to /index/relationship/foo_rels/15/23/100 where 15 is the key, 23 is the value, 100 is the relationship id)? ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] 10 questions
Hi anders, thanks for the clarification. On Fri, Sep 2, 2011 at 8:32 AM, Anders Nawroth and...@neotechnology.com wrote: Hi! 2011-09-01 03:29, Linan Wang: 2, does index operation add/remove/modify threadsafe, don't need lock/transaction? 3, does it simple property writing operations also need to be wrapped inside transaction? if so, in the imdb exmaple tutor/domain/MovieImpl.java underlyingNode.setProperty is used neither within transaction, nor put into a save method, do all setProperty works inside a transaction? All modifying operations need to be performed inside a transaction. In most cases it makes sense to perform multiple operations in a single transaction. For example in a web application it may be a good fit to wrap the handling of one request in a transaction. So if a method doesn't start a transaction, it just means that it's handled at a higher level in the application. got this part. then do you suggest to leave indexing action outside of node operation? say i have a domain model and it handles indexing actions along with underlying nodes modification, then in an web app, should I wrap only nodes operations inside transaction and do indexing only after it success? /anders 4, what's the best practice to do bulk insertion when running (not seed initial data)? i read post says that too many insertions within a transaction may lead to memory problem? what's the proper mount of insertion within a transaction? 5, is there a suggested max length for string/array property? would it be better to put into sql? 6, say a facebook user may likes thousands of things, and these things are sparsly connected. in this case, things should be modeled as nodes or array property? 7, where can i find an example to use domain models with serverplugin? i want to put my data in a standalone server and just use the serverplugin, unmanaged extension. should i just put the domain models into the same serverplugin jar? 8, the warning in the documentation about unmanaged extension is scary. what i can see is that people may use bad ways, instead of Iterator/IteratorWrappers. any comment on this? 9, i'm not sure if it's trival: find out users who are only 2 relationships a way (use twitter example: my followees' followers), live in same city, group by age and gender. also retrieve all their followees. i want to do the traversal in java, where can i find an examples? 10, i've had horrible experience in turning jvm options. have neo4j been running on Zing JVM, hp nonstop jvm? are they better options? thanks in advance Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] 10 questions
hi
On Fri, Sep 2, 2011 at 10:18 AM, Anders Nawroth
and...@neotechnology.com wrote:
Hi!
All modifying operations need to be performed inside a transaction. In
most cases it makes sense to perform multiple operations in a single
transaction. For example in a web application it may be a good fit to
wrap the handling of one request in a transaction. So if a method
doesn't start a transaction, it just means that it's handled at a higher
level in the application.
got this part. then do you suggest to leave indexing action outside of
node operation? say i have a domain model and it handles indexing
actions along with underlying nodes modification, then in an web app,
should I wrap only nodes operations inside transaction and do indexing
only after it success?
Seems like the node and index modifications belong in the same
transaction, to make sure any modifications to nodes are always
reflected in the indexes as well. Otherwise they could get out of sync
if your application crashes after the commit of the first,
node-modifying transaction.
it seems confusing. if indexing actions wrapped inside a transaction
and the transaction fails, will indexing action automatically get
rollback? think this example:
class User{
public void dosomething(){
//node actions
//index actions
}
}
class Ext extends ServerPlugin{
public action(){
// get an array of users;
Transaction tx = graphDb.beginTx();
try
{
... // operations that work with the graph
for(User u:users){
u.dosomething();
}
tx.success();
}
finally
{
tx.finish();
}
}
}
/anders
/anders
4, what's the best practice to do bulk insertion when running (not
seed initial data)? i read post says that too many insertions within a
transaction may lead to memory problem? what's the proper mount of
insertion within a transaction?
5, is there a suggested max length for string/array property? would it
be better to put into sql?
6, say a facebook user may likes thousands of things, and these
things are sparsly connected. in this case, things should be modeled
as nodes or array property?
7, where can i find an example to use domain models with serverplugin?
i want to put my data in a standalone server and just use the
serverplugin, unmanaged extension. should i just put the domain models
into the same serverplugin jar?
8, the warning in the documentation about unmanaged extension is
scary. what i can see is that people may use bad ways, instead of
Iterator/IteratorWrappers. any comment on this?
9, i'm not sure if it's trival: find out users who are only 2
relationships a way (use twitter example: my followees' followers),
live in same city, group by age and gender. also retrieve all their
followees. i want to do the traversal in java, where can i find an
examples?
10, i've had horrible experience in turning jvm options. have neo4j
been running on Zing JVM, hp nonstop jvm? are they better options?
thanks in advance
Best regards
Linan Wang
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Re: [Neo4j] 10 questions
great. i thought transaction only applies to nodes operations. seems
it also including indexing. it's handy!
other 9 questions? :)
On Fri, Sep 2, 2011 at 12:55 PM, Anders Nawroth
and...@neotechnology.com wrote:
Hi!
Seems like the node and index modifications belong in the same
transaction, to make sure any modifications to nodes are always
reflected in the indexes as well. Otherwise they could get out of sync
if your application crashes after the commit of the first,
node-modifying transaction.
it seems confusing. if indexing actions wrapped inside a transaction
and the transaction fails, will indexing action automatically get
rollback? think this example:
Yes, it will be rolled back - that's the point of performing multiple
operations in the same transaction.
/anders
class User{
public void dosomething(){
//node actions
//index actions
}
}
class Ext extends ServerPlugin{
public action(){
// get an array of users;
Transaction tx = graphDb.beginTx();
try
{
... // operations that work with the graph
for(User u:users){
u.dosomething();
}
tx.success();
}
finally
{
tx.finish();
}
}
}
/anders
/anders
4, what's the best practice to do bulk insertion when running (not
seed initial data)? i read post says that too many insertions within a
transaction may lead to memory problem? what's the proper mount of
insertion within a transaction?
5, is there a suggested max length for string/array property? would it
be better to put into sql?
6, say a facebook user may likes thousands of things, and these
things are sparsly connected. in this case, things should be modeled
as nodes or array property?
7, where can i find an example to use domain models with serverplugin?
i want to put my data in a standalone server and just use the
serverplugin, unmanaged extension. should i just put the domain models
into the same serverplugin jar?
8, the warning in the documentation about unmanaged extension is
scary. what i can see is that people may use bad ways, instead of
Iterator/IteratorWrappers. any comment on this?
9, i'm not sure if it's trival: find out users who are only 2
relationships a way (use twitter example: my followees' followers),
live in same city, group by age and gender. also retrieve all their
followees. i want to do the traversal in java, where can i find an
examples?
10, i've had horrible experience in turning jvm options. have neo4j
been running on Zing JVM, hp nonstop jvm? are they better options?
thanks in advance
Best regards
Linan Wang
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Re: [Neo4j] 10 questions
Thanks! The Matrix example I was referring to http://docs.neo4j.org/chunked/stable/indexing-add.html Sent from my iPad On 1 Sep 2011, at 21:21, Peter Neubauer peter.neuba...@neotechnology.com wrote: Hi there, would love to answer but had no time today, will try tomorrow. Also, very valid points about the docs, will try to put as much of the answers into the docs as possible. What Matrix example are you looking at? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/- Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Thu, Sep 1, 2011 at 10:10 PM, wangii tali.w...@gmail.com wrote: anyone show some love ;) seriously, the product is great but not the documentation. e.g. about the general rule for choosing property or relationship: in the matrix example, the year of a movie should be modelled as relationship since every year lots of movies are produced. -- View this message in context: http://neo4j-community-discussions.438527.n3.nabble.com/Neo4j-10-questions-tp3300093p3302418.html Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
[Neo4j] 10 questions
hi, got some questions not found simple answers from the documents. i bet some of them are pretty primitive, bear with me please. 1, what's the general rule for choosing properties or relationship? say a User lives in a City, which just contains a simple int id value. to find users live in a city, i can do a simple traversal, of all user nodes, or find the city node first, then collect all the users. seems to me both ways work and share same level of performance. (am i right here?) 2, does index operation add/remove/modify threadsafe, don't need lock/transaction? 3, does it simple property writing operations also need to be wrapped inside transaction? if so, in the imdb exmaple tutor/domain/MovieImpl.java underlyingNode.setProperty is used neither within transaction, nor put into a save method, do all setProperty works inside a transaction? 4, what's the best practice to do bulk insertion when running (not seed initial data)? i read post says that too many insertions within a transaction may lead to memory problem? what's the proper mount of insertion within a transaction? 5, is there a suggested max length for string/array property? would it be better to put into sql? 6, say a facebook user may likes thousands of things, and these things are sparsly connected. in this case, things should be modeled as nodes or array property? 7, where can i find an example to use domain models with serverplugin? i want to put my data in a standalone server and just use the serverplugin, unmanaged extension. should i just put the domain models into the same serverplugin jar? 8, the warning in the documentation about unmanaged extension is scary. what i can see is that people may use bad ways, instead of Iterator/IteratorWrappers. any comment on this? 9, i'm not sure if it's trival: find out users who are only 2 relationships a way (use twitter example: my followees' followers), live in same city, group by age and gender. also retrieve all their followees. i want to do the traversal in java, where can i find an examples? 10, i've had horrible experience in turning jvm options. have neo4j been running on Zing JVM, hp nonstop jvm? are they better options? thanks in advance Best regards Linan Wang ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
