Re: Options for Bulk Read/Bulk Export
To add to Mark's suggestions there is also a multiQuery option in janusgraph-core. Notice, it's internal API and not Gremlin. Thus, it might be unavailable to you if you can access JanusGraph internal API for any reason.
If you work with multiQuery like `janusGraph.multiQuery().addAllVertices(yourVertices).properties()` then make sure you transaction cache is at least the size of `yourVertices.size()`. Otherwise, additional calls might be executed to your backend which could be not as efficient.