Bryce, On Fri, Sep 2, 2011 at 1:44 AM, Bryce <bryc...@gmail.com> wrote:
> Hi, > > I have been looking at performance options for Neo4j as presently I have > been observing a number of performance issues. I am still investigating > the > way to get the best performance out of what I am doing, and one thing it > might be are longer running transactions stopping other work going on (but > thats an aside to what this message is about). > > One of the things that I investigated using was the IndexedRelationship > work > by Niels. Thought I would give a bit of feedback, although I haven't quite > got this implemented at present. > > 1) I had to change the IndexedRelationshipExpander to be a public class in > order to use it outside the package its in. > > Maybe you can fork the project and add your fix there? > 2) IndexedRelationship assumes only one tree root per node, whereas the > expander allows for multiple (IndexedRelationship uses > getSingleRelationship > vs expander using getRelationships then matching on tree name). Having > multiple would obviously be good as it means you could have two types of > relationships covered by IndexedRelationship's. > > 3) Might pay to make it clear in the Javadocs for IndexedRelationship that > the comparator can't be an anonymous inner class. > > See above, sounds like a good contribution! > Then I have some questions about usage of this. First a little background > of the model I have, from reading a few things it seems quite standard. > There are a lot of "document" nodes each of which have a relationship with > multiple "tag" nodes. Documents generally have in the order of 10-20 tags, > and tags can have as few as 1 document and sometimes tens of thousands. > When tags are viewed through the UI they are almost always displayed with > a > descending date ordered list of documents. Seemed to be to fit quite well > with IndexedRelationship. > > 1) I was thinking of having a switch over point at say around 500 documents > for a given node where I will switch from using normal relationships to an > IndexedRelationship as I was thinking at small numbers of relationships > normal relationships would be quicker. Would that be correct, or not worth > it? > > 2) On the tag end (which is the incoming end of the document-tag > relationship) I was going to use a IndexedRelationshipExpander which would > cover the case of whether the relationship was done through normal > relationships, or through an IndexedRelationship. I also need to get a set > of tags from the document end where their may be both normal relationships, > and relationships coming from multiple IndexedRelationship's. From looking > at it IndexedRelationshipExpander doesn't cover the reverse direction, but > I > would imagine using a relationship expander here would be correct. What > would the best way of doing this be? > > As an aside it may be a good idea to note in the configuration settings > page: > > http://wiki.neo4j.org/content/Configuration_Settings#Optimizing_for_traversals_example > that -XX:+UseNUMA > only works when using the Parallel Scavenger garbage collector (default > or -XX:+UseParallelGC) not the concurrent mark and sweep one. Based on > Changed in the Wiki, see http://wiki.neo4j.org/content/Configuration_Settings#Configuring_the_memory_for_the_JVM. Thanks for the hint! We should get this page into the manual. /peter > > Cheers > Bryce > _______________________________________________ > 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
