2010/10/28 david lightstone <david.lightst...@gmail.com> > Mattias, > > So Direction.BOTH means to traverse from both sides, not that the > relationships are directed, correct? I completely misinterpreted that and > used Direction.OUTGOING to indicate that my relationships were not > bidirectional. Thank you! >
Direction.BOTH means traverse relationships disregarding their directions... it _doesnt_ mean traverse from both sides, that's an implementation detail of the ShortestPath algorithm. Try to keep those two meanings separate! So your initial interpretation was correct regarding Direction.BOTH. > > And I will look into using the REST API to try and keep the JVM up as long > as possible. I was thinking of it exactly as you had mentioned it should > not > be (an SQLConnection equivalent). In fact, I just moved my database from > MySQL tables into Neo4j. In the end I am trying to interface the Neo4j > database with a PHP front end (which I had already developed for use with > the old MySQL database). > > I was looking at the PHP-REST link on the Wiki but was taken to a broken > link at: > https://svn.neo4j.org/laboratory/components/rest/ > > Thanks again. > > David. > > On Thu, Oct 28, 2010 at 3:39 PM, Mattias Persson > <matt...@neotechnology.com>wrote: > > > 2010/10/28 david lightstone <david.lightst...@gmail.com> > > > > > Thank you both for the quick replies. > > > > > > My dbs are of the following size: > > > > > > FILESIZES > > > ---------------- > > > neostore.nodestore.db 70MB > > > neostore.propertystore.db 583MB > > > neostore.relationshipstore.db 6.6GB > > > neostore.propertystore.db.strings 1 GB > > > > > > I played around with the props configuration, trying many different > > values. > > > here is what I currently have in it. It seems like caching does not > work > > > well at all when I use the configuration. > > > > > > CONFIGURATION > > > -------------------------- > > > neostore.nodestore.db.mapped_memory=80M > > > neostore.relationshipstore.db.mapped_memory=2500M > > > neostore.propertystore.db.mapped_memory=500M > > > neostore.propertystore.db.strings.mapped_memory=100M > > > neostore.propertystore.db.arrays.mapped_memory=0M > > > > > > Peter, I have seen that it does work faster in Windows than in Linux > but > > > again Windows has 2x128GB SSD in RAID 0 (~300MB/s read). I have also > > tried > > > running using the parameters "-Xms2000M -Xmx4000M -server" > > > > > > Mattias, I do want to do a BFS, finding the shortest path between two > > given > > > nodes that I pass in as parameters. One thing I do not understand about > > > caching (perhaps I am going about this entirely wrong) is how does the > > > database stay in memory? In my Neo4jBFS.java file, I call the following > > > commands: > > > > > > > That isn't a very efficient way of finding the shortest path between two > > nodes. Instead try out an algorithm written for just that in the > graph-algo > > component <http://components.neo4j.org/neo4j-graph-algo/> and in that > page > > you can see a usage example of the ShortestPath algorithm. Key benefits > > with > > that implementation are traversing from both directions and using less > > memory. > > > > > > > > > > graphDb = new EmbeddedGraphDatabase (DB_PATH); > > > /* do stuff */ > > > indexService.shutdown(); > > > graphDb.shutdown(); > > > > > > > The program is called with the following command line: > > > > > > java Neo4jBFS sourceNode targetNode maxDepth (and the Xmx, Xms, server > > > command lines as described above) > > > > > > Wouldn't that make it always the first instance of > GraphDatabaseService? > > > How > > > can I get around that and have it always running in the background? If > > > there > > > is any code that you would like me to post to please let me know. > > > > > > Thank you again for the prompt replies! > > > > > > > You generally want to keep your database JVM alive as long as possible to > > gain the effects of the cached values. Don't look at an > > EmbeddedGraphDatabase as the equivalent to an SQLConnection or something, > > it > > shouldn't be closed as soon as possible. > > > > If you plan on having a neo4j graph database sitting and answering these > > shortest path requests then you could either bring up a standalone REST > > server <http://components.neo4j.org/neo4j-rest/> which exposes a REST > API, > > and also includes the shortest path algorithm. Or deploy it in a > container, > > f.ex. a web container or Spring. > > > > > > > > > > > > David. > > > > > > On Thu, Oct 28, 2010 at 2:54 PM, Mattias Persson > > > <matt...@neotechnology.com>wrote: > > > > > > > Do you actually want to do a BFS (assuming that means breath first > > > search) > > > > and get all those paths back, or are you just testing performance? > Also > > > if > > > > it's the first run for that GraphDatabaseService instance you're > > > basically > > > > testing your I/O performance on your hard drive since everything will > > > have > > > > to be read up into memory. Consecutive runs should be much faster. > > > > > > > > 2010/10/28 david lightstone <david.lightst...@gmail.com> > > > > > > > > > Hi everyone, > > > > > > > > > > I'm running Neo4j on both Ubuntu and Windows 7 boxes. I have a > > dataset > > > > with > > > > > 200 million edges and 10 million nodes with a median branching > factor > > > of > > > > > about 50 outgoing, directed edges/node. I'm trying to run the BFS > > > search > > > > on > > > > > the data but am fairing unsuccessful in being able to do so in a > > timely > > > > > fashion. I have tried to follow the advice on > > > > > http://wiki.neo4j.org/content/Neo4j_Performance_Guide but I still > > have > > > > > queries that can take up to 300 seconds or so to run. My Ubuntu box > > has > > > > 6GB > > > > > of RAM, and is running on a 7200RPM hard drive, while my windows > box > > > has > > > > > 8GB > > > > > RAM and is running off of SSDs (HDtune reports ~300 MB/s reads). > > > > > > > > > > I had also added an index for the nodes. > > > > > > > > > > Can anyone offer advice on why this process may be taking so long? > > The > > > > CPU > > > > > usage on both is very low (2-5%) and I'm pretty sure the whole > thing > > is > > > > HDD > > > > > i/o limited, but I was wondering if there were any techniques or > > > anything > > > > > to > > > > > actually get the query to go any faster? > > > > > > > > > > Judging by what I had read about Neo4j in descriptions I assumed > that > > > my > > > > > data size was not too large to justify a long BFS (the paths can > take > > > up > > > > to > > > > > 300 seconds just 4 nodes away.) > > > > > > > > > > Thank you in advance. > > > > > _______________________________________________ > > > > > Neo4j mailing list > > > > > User@lists.neo4j.org > > > > > https://lists.neo4j.org/mailman/listinfo/user > > > > > > > > > > > > > > > > > > > > > -- > > > > Mattias Persson, [matt...@neotechnology.com] > > > > Hacker, Neo Technology > > > > www.neotechnology.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 > > > > > > > > > > > -- > > Mattias Persson, [matt...@neotechnology.com] > > Hacker, Neo Technology > > www.neotechnology.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 > -- Mattias Persson, [matt...@neotechnology.com] Hacker, Neo Technology www.neotechnology.com _______________________________________________ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
