如何查找有关在以Cassandra作为数据存储的Titan / Rexster图形数据库上创建的索引的信息

Question

I have a Rexster/Titan + Cassandra configuration. I have created unique index over vertex properties. How can I verify the index has created properly? and also to check the other properties such as uniqueness and any other information about the created index?

Answer 1

As you are using Titan, you can use the TitanManagement API:

gremlin> g = TitanFactory.open('conf/titan-berkeleydb-es.properties')
==>titangraph[berkeleyje:/home/smallette/jvm/titan-0.5.4-hadoop1/conf/../db/berkeley]
gremlin> GraphOfTheGodsFactory.load(g)
==>null
gremlin> mgmt = g.getManagementSystem()
==>com.thinkaurelius.titan.graphdb.database.management.ManagementSystem@6ac756b
mgmt.getGraphIndexes(Vertex.class).collect{[it.name,it.fieldKeys.collect{it.cardinality}]}
==>[name, [SINGLE]]
==>[vertices, [SINGLE]]
gremlin> mgmt.rollback()
==>null

You can either issue the query as I did from the Gremlin Console or you should be able to simply issue the same query like that to Rexster's Gremlin Extension to get that result. Be sure to call rollback (or commit ) to close the management API transaction, especially if using Rexster (Rexster doesn't auto-manage those).