TITAN

问题 I am learning Titan database. I have run it successfully in local-mode. Now, I am trying to use Titan database in "Remote Server Mode" introduced in Titan-documentation. My Titan version is Titan-1.0.0-hadoop1. I have clusters in my LAN including cloud12 and cloud13 . I installed hadoop-1.2.1 on it, the master is cloud12 and the slave is cloud13 . I want to test the performance about create a graph, so I design to start my Hbase-0.98.20 in pseudo-distributed-mode on machine cloud12 with

问题 I am trying to fetch edge property value between two vertices and getting below exception java.lang.ClassCastException: java.lang.String cannot be cast to scala.runtime.Nothing$ Env: Titan InMemory Code : val age = Key[Int]("age") A ---("knows",age -> 10) --> B Gremlin query: graph.traversal().V().has("ID", "A").bothE("knows").as("x").otherV() .has("ID", "B").select("x").properties("age").headOption().get output : p[age->10] graph.traversal().V().has("ID", "A").bothE("knows").as("x").otherV()

问题 I am starting to work with Titan and I am using cassandra as backend store. When I start titan.sh cassandra and elasticsearch were started but the gremlin server did not. I was looking at titan.sh and I have seen that it start gremlin server with conf/gremlin-server/gremlin-server.yaml. The problem is that the gremlin-server.yaml is configured as this: graphs: { graph: conf/gremlin-server/titan-berkeleyje-server.properties} Using BerkeleyDb. I have not seen the cassandra.yaml for Gremlin

问题 In older version of Titan DB (ver 0.5.2) the TitanVertex and TitanEdge implement TitanElement interface that has method getProperties(String key) that I used to retrieve the element properties values. This method was removed in new version of Titan (I am using version 1.0.0). Instead of this method I found valueOrNull(PropertyKey key) that does the same thing but receives PropertyKey as parameter and not String as key name. What is the best way to retrieve the property value/values only using

问题 I am going to update entire value of list property and set a new value for that in Titan 1.0, for single cardinality I can use vertex.property("single_property",new_value) ,and overwrite the whole value but for the cardinality of type List, the new value will be added to the property (it will not overwrite the whole value). Moreover, if I remove the property and add a new value, in the same transaction it seems that the whole operation will be ignored by Titan! Therefore, my question would be

问题 I have a titan graph with two sets of vertices, one for UserID and another for Products. The edges between the UserID and Product vertices contain the "Dates" when products were purchased. I am looking for a gremlin query that can give me a groupcount of userids by the last product purchased For example if had data like below UserID,Date,Product A,2016-01-01,'Razor' A,2016-01-02,'Toothpaste' B,2016-02-01,'Toothpaste' B,2016-02-02,'Razor' C,2016-01-04,'Toothpaste' I am looking for an output

问题 I am using Elastic Search with Titan. How can I do pagination in ES with titan? I saw THIS and so was trying this: Iterable<Result<Vertex>> vertices = g.indexQuery("search","v.testTitle:(mytext)") .addParameter(new Parameter("from", 0)) .addParameter(new Parameter("size", 2)).vertices(); for (Result<Vertex> result : vertices) { Vertex tv = result.getElement(); System.out.println(tv.getProperty("testTitle")+ ": " + result.getScore()); } The thing is it return all 4-5 records not in the size of

问题 I get an exception when calling com.tinkerpop.blueprints.Edge.getLabel on some vertex edges : java.lang.IllegalStateException: Could not find type for id: 630 at com.google.common.base.Preconditions.checkState(Preconditions.java:200) at com.thinkaurelius.titan.graphdb.types.vertices.TitanTypeVertex.getName(TitanTypeVertex.java:30) at com.thinkaurelius.titan.graphdb.transaction.StandardTitanTx$VertexConstructor.get(StandardTitanTx.java:321) I can solve this issue by removing all vertex and

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 3 years ago . please help me , I'm quite confuse while deciding to use graph database , I'm developing a Social networking website . so please suggest me which I have to use . I developing this project using spring and liferay 6.2. Please help me . Thanks in advance. 回答1: Titan as product is dead about 2 weeks ago. DataStax

问题 I've noticed that relationships cannot be properly stored in C* due to its 100MB partition limit, denormalization doesn't help in this case and the fact that C* can have 2B cells per partition neither as those 2B cells of just Longs have 16GB ?!?!? Doesn't that cross 100MB partition size limit ? Which is what I don't understand in general, C* proclaims it can have 2B cells but a partition sizes should not cross 100MB ??? What is the idiomatic way to do this? People say that this an ideal use