TITAN

问题 I downloaded and unziped the titan.zip and used the command ./titan.sh -v start . Now I get the output: ./titan.sh -v start Forking Cassandra... OpenJDK 64-Bit Server VM warning: The UseParNewGC flag is deprecated and will likely be removed in a future release Running nodetool statusthrift.Error: Config file not found: /usr/lib64/jvm/java-1.9.0-openjdk-1.9.0/jre/conf/management/management.properties ...... timeout exceeded (60 seconds) See /home/hausi/Documents/titan-0.5.4-hadoop2/bin/../log

问题 I was using Titan 1.0 with gremlin server to create and delete vertex. I want to implement this logic in my .net project. I wonder if there is any pre build plugin for titan and gremlin server in asp.net? Currently i'm directly using command prompt to create and delete the required vertices and edges. how can I implement it in my .net MVC project? 回答1: I've created one class in my project for interacting with Gremlin server using REST API. you can make small changes to make it work for you.

问题 I have a Titan graph database witha set of vertices connected by an edge with a property named "property1". Is it possible to write a Gremlin (or anything else Titan would support) query to: Find all edges that have a value for "property1" that is seen 5 or less times. In SQL I would use "Group By", in MongoDB I would use one of the aggregate functions. I am thinking this may be a job for Furnace/Faunus? 回答1: You can do this by iterating all edges and using groupBy . Here's an example with

问题 I am new to titan. I want to use titan with cassandra database. But when I start the gremlin server and try to load a graph using command - graph = TitanFactory.open("conf/titan-cassandra.properties") it gives me the following error - Could not instantiate implementation: com.thinkaurelius.titan.diskstorage.es.ElasticSearchIndex I dont want to use elastic search. Can anyone help. 回答1: You are probably trying to connect to an existing graph that was previously configured to use Elasticsearch.

问题 It looks like we can get Titan 1.0 use custom long ids by setting "graph.set-vertex-id" to true. Is there some way to use non-long (i.e. String) ids as Vertex Ids? Seeing that the Tinkerpop api supports Strings, and there's a feature called "StringIds", is there some way of enabling that feature? I'm using Titan with Cassandra. 回答1: I think this goes against Titan's internal structure. One of the Titan devs recommends here to just use your own indexed property. This is reiterated here and

问题 I am using TITAN 0.4, and gremlin for traversals. My requirement is to identify duplicate vertices in graph, and to merge those. There are > 15 M vertices in graph. gremlin> g.V.has('domain').groupBy{it.domain}{it.id}.cap ==>{google.com=[4], yahoo.com=[16, 24, 20]} I am able to group the vertices, but I need only those domains(vertices) which exists more than once. In the above example, I need to return only ==>{yahoo.com=[16, 24, 20]} The key "domain" is indexed, if that makes any difference

问题 I'm using the following code to load Titan: TitanFactory.Builder config = TitanFactory.build(); config.set("storage.backend", "berkeleyje"); config.set("storage.directory", DIRECTORY); //config.set("storage.conf-file", "file:////" + DIRECTORY + "/cassandra/cassandra.yaml"); config.set("index." + INDEX_NAME + ".backend", "elasticsearch"); config.set("index." + INDEX_NAME + ".DIRECTORY", DIRECTORY + File.separator + "es"); config.set("index." + INDEX_NAME + ".elasticsearch.local-mode", true);

问题 I want to add property to a vertex property. In gremlin i add property "phone" to vertex property "places" that has value is "place1" g.V(v).properties('places').hasValue('place1').property('phone',"123456789") It worked ok without using transaction commit. But when i used this way in java code, it not worked. So in java code, how to add a property to vertex property? Thank for your help. 回答1: You need to iterate() the traversal. g.V(v).properties('places').hasValue('place1').property('phone'

问题 I'm experimenting with Bulbs to interface with a graph database. ( Production will use Titan, locally Neo4j seems best for experimenting ). I can't wrap my head around this concept... Bulbs shows how to create new Vertices... >>> james = g.vertices.create(name="James") >>> julie = g.vertices.create(name="Julie") >>> g.edges.create(james, "knows", julie) Digging into the docs, I can replace that with a "get or create" as well : >>> james = g.vertices.get_or_create('name',"James",{'name':'james

问题 I have stuck with my TitanDB, Django1.8 and Mogwai0.7.7 package. I have Graph database titan/cassandra on localhost dev machine, and after creating wrong queries in rexster gremlin web interface my Django Object Graph Mapper mogwai stopped to work. Titan is still working and data are present but Django stopped to work with it. File "/Users/x/envs/graph/lib/python2.7/site-packages/rexpro/connectors/base.py", line 281, in close_transaction raise exceptions.RexProScriptException("transaction is