In the JanusGraph document, I got the following description: "JanusGraph automatically builds vertex-centric indexes per edge label and property key. That means, even with thousands of incident battled edges, queries like g.V(h).out('mother') or g.V(h).values('age') are efficiently answered by the local index.
Vertex-centric indexes cannot speed up unconstrained traversals which require traversing through all incident edges of a particular label. Those traversals will become slower as the number of incident edges increases. Often, such traversals can be rewritten as constrained traversals that can utilize a vertex-centric index to ensure acceptable performance at scale."
I got two questions:
1,In the first paragraph, we can see the vertex-centric indexes can speed up queries like g.V(h).out('mother') or g.V(h).values('age'), but the next paragraph says vertex-centric indexes can not speed up unconstrained traversals which require traversing through all incident edges of a particular label. Is this contradictory？
2,And in the statement ”JanusGraph automatically builds vertex-centric indexes per edge label and property key.“， the property key means the vertex's property key but not the edge label property key, right?
Thanks advance!