Re: Query requires iterating over all vertices


Jason Plurad <plu...@...>
 

No, it is not a bug. It is a warning letting you know that there is a query that is doing a global scan of all vertices. In this case, the specific call is `g.V().count().next()` which is trying to determine whether there is any data in the graph. Something like `g.V().hasNext()` would be a less expensive check, although it would still issue the warning.

This small example can get away a call like this because there are only 12 vertices in the loaded graph, but it would be an expensive operation if there were 1 billion vertices.

Thanks for the feedback.
-- Jason


On Thursday, May 18, 2017 at 12:36:05 PM UTC-4, Ярослав Станко wrote:
Hello!


Why is there a warning in the log?

"WARN org.janusgraph.graphdb.transaction.StandardJanusGraphTx - Query requires iterating over all vertices [()]. For better performance, use indexes"

In my project the same thing.

Is this a bug? How to fix it?

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