Queries slow when no type on bound nodes

[cbizon]

In a trapi qnode, you can give ids and/or categories. If you give an id, but no category, the query is possibly going to be slow. This is because the underlying graph has indices to find nodes with identifiers, but neo4j bases its indices on labels (categories). So since the generated cypher doesn't know what type the thing is, the index is not hit, and the planner does stupid (and slow) things.

The fix is probably simply to ensure that bound qnodes always have a category, of at least "NamedThing". This could be done as a pre-process on the trapi input or in the (already somewhat convoluted) cypher generation.