Hi there,
Without having too much insight in the concurrency of things, Neo4j
locks on node level. That means, if two transactions in different
threads are trying to modify the same nodes or relationships, an
exception will be thrown or the transactions will be queued.
Also, I am not sure how the lucene index is behaving in multiple
threads, since we are wrapping it to be able to provide transactional
support, which is not built into Lucene itself.
Mattias, do you have any details on that?
/peter
On Friday, March 18, 2011, 孤竹 <ho...@foxmail.com> wrote:
> hi,
>
>
> Sorry for disturb you , I am a chinese engineer , Excused for my bad
> english :) .
>
>
> Recently, I am learning Neo4j and trying to use it in my project . But
> When I make a Pressure on neo4j with 5 theads , 10 theads, 20 and 30, I found
> the nodes inserted to the Neo4J is not change obvious (sometimes not change ~
> ~! ). Does it not matter with threads ? the kenerl will make it Serial ? Is
> there any documents or something about The performance of Neo4j ? thanks for
> your help
>
>
>
> The program as follows:
> I put this function in ExecutorService ,with 5/10/30 threads. then test
> for the nodes inserted into at same time .(The counts have not changed
> obviously)
>
>
> Transaction tx = null;
> Node before = null;
> try {
> for (int i = 0; i < 1000000; i++) {
> if(stop == true){
> return;
> }
> if (graphDb == null) {
> return;
> }
> try {
> if (tx == null) {
> tx = graphDb.beginTx();
> }
> // 引用计数加1
> writeCount.addAndGet(1);
> int startNodeString =
> name.addAndGet(1);
> Node start =
> getOrCreateNodeWithOutIndex(""
> + startNodeString);
> if (before == null) {
> // 根节点.哈哈哈 I got U
> Node root =
> graphDb.getNodeById(0);
>
> root.createRelationshipTo(start, LEAD);
> }
> if (before != null) {
>
> before.createRelationshipTo(start, LOVES);
> }
> int endNodeName = name.addAndGet(1);
> Node end =
> getOrCreateNodeWithOutIndex("" + endNodeName);
> start.createRelationshipTo(end,
> KNOWS);
> before = end;
> // 每一千次 commit一次
> if (i % 100 == 0) {
> tx.success();
> tx.finish();
> tx = null;
> }
> } catch (Exception e) {
> System.out.println("write : = " + e);
> }
> }
> } catch (Exception e) {
> } finally {
> tx.finish();
> }
> }
> _______________________________________________
> 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
