Faster JanusGraph queries

Previously my janusgraph was working fine with nearly 1000 elements. I made my graph 100k and now some queries are very slow. I'm using Cassandra as database backend and elastic search as index backend.

For example g.V().hasLabel('Person').union(count(), range(0, 15)) this takes 1.3 minutes. I just want to get 15 "Person". It should be fast.

g.E().count() takes 1.4 minutes. Why it is soo slow? I only have 200k nodes and 400k edges.

I also have some composite indexes for my "Person" node type. I have indexes for all the properties of "Person" node type

thanks for any advice

Solution 1:

Counting vertices with a specific label is a frequent use case that JanusGraph can only address by running a full table scan. So, for larger graphs counting becomes unbearably slow. Because the usecase is so frequent, an issue was created for it.

If you use Janusgraph with an indexing backend for mixed indexes. it is possible to run a so-called direct index query in JanusGraph that can return totals of index hits in a speedier way. This does not work on label filters, though, but on indexed properties.