Titan db how to list all graph indexes

Question

I've been looking at the management system but some things still elude me. Essentially what I want to do is:

• List all Edge based indexes (including vertex centric).
• List all Vertex based indexes (on a per label basis if the index is attached to a label).

It's basically like mapping out the graph schema.

I've tried a few things but I only get partial data at best.

g.getIndexdKeys(<Vertex or Edge>); 
//basic information. Doesn't seem to return any buildEdgeIndex() based indexes

mgmt.getVertexLabels(); 
// gets labels, can't find a way of getting indexes attached to these labels.

mgmt.getGraphIndexes(Vertex.class); 
// works nicely I can retrieve Vertex indexes and get pretty much any 
// information I want out of them except for information regarding 
// indexOnly(label). So I can't tell what label these indexes are attached to.

mgmt.getGraphIndexes(Edge.class); 
// doesn't seem to return any buildEdgeIndex() indexes.

Any help filling the void would be helpful.

Id like to know:

• How can I find the indexes attached to a label (or label attached to an index) via indexOnly()
• How do I list the edge indexes set via buildEdgeIndex() and their respective edge Labels?

Thanks in advance.

Extra information: Titan 0.5.0, Cassandra backend, via rexster.

Answer 1

it's not really straight forward, hence I'm going to show it using an example.

Let's start with the Graph of the Gods + an additional index for god names:

g = TitanFactory.open("conf/titan-cassandra-es.properties")
GraphOfTheGodsFactory.load(g)
m = g.getManagementSystem()
name = m.getPropertyKey("name")
god = m.getVertexLabel("god")
m.buildIndex("god-name", Vertex.class).addKey(name).unique().indexOnly(god).buildCompositeIndex()
m.commit()

Now let's pull the index information out again.

gremlin> m = g.getManagementSystem()
==>com.thinkaurelius.titan.graphdb.database.management.ManagementSystem@2f414e82

gremlin> // get the index by its name
gremlin> index = m.getGraphIndex("god-name")
==>com.thinkaurelius.titan.graphdb.database.management.TitanGraphIndexWrapper@e4f5395

gremlin> // determine which properties are covered by this index
gremlin> gn.getFieldKeys()
==>name

//
// the following part shows what you're looking for
//
gremlin> import static com.thinkaurelius.titan.graphdb.types.TypeDefinitionCategory.*

gremlin> // get the schema vertex for the index
gremlin> sv = m.getSchemaVertex(index)
==>god-name

gremlin> // get index constraints
gremlin> rel = sv.getRelated(INDEX_SCHEMA_CONSTRAINT, Direction.OUT)
==>com.thinkaurelius.titan.graphdb.types.SchemaSource$Entry@5162bf3

gremlin> // get the first constraint; no need to do a .hasNext() check in this
gremlin> // example, since we know that we will only get a single entry
gremlin> sse = rel.iterator().next()
==>com.thinkaurelius.titan.graphdb.types.SchemaSource$Entry@5162bf3

gremlin> // finally get the schema type (that's the vertex label that's used in .indexOnly())
gremlin> sse.getSchemaType()
==>god

Cheers, Daniel