Vertices can be retrived through Edge Query(g.E()) but not through Vertex Query (g.V())

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Krishna Sailesh

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Jun 5, 2020, 9:16:29 AM6/5/20
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Hi Team

we have a issue janusgraph DB Data, when we try to fetch data with vertex traversal (g.V()) we are not getting data, but when i try to fetch the data from Edge traversal (g.E().hasLabel("topology").bothV()) we can see the vertex reference to that edge.
               gremlin> g.E()
               06:56:08 WARN  org.janusgraph.graphdb.transaction.StandardJanusGraphTx  - Query requires iterating over all vertices [()]. For better performance, use indexes
               ==>e[m4n-fug-bv9-39k][20536-topology->4232]
               gremlin> g.V(4232)
               gremlin>
               gremlin> g.E().bothE().valueMap()
               ==>[id:[123],name:[test],age:[30],gender:[male]]
               ==>[id:[13],name:[test1],age:[34],gender:[male]]
               gremlin> g.V().outE().inV().valueMap()
               ==>[id:[123],name:[test],age:[30],gender:[male]]
             Note: i have so many edges in JanusGraph just given the data which has the issue

here are my questions.

1.why can't we get the vertex through g.V() but  we can get it with g.E().
2.is this issue is caused because, as we directly remove/drop vertex with out deleting/removing edges related to the vertex. if yes, but when we try to remove the vertex
   observed that edges of that vertices are deleted which is taken care of janusgraph.
3.may be this issue is caused due to parallel transcation on edge and vertex same time like one transcation is adding edge on vertex and other transcation id trying to  delete  vertex.

can some one  please help me to explain  how this thing is happening and solve this issue.


Thanks
Krishna Jalla





Abhay Pandit

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Jun 5, 2020, 10:08:17 AM6/5/20
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Hi Krishna,

For me it seems like some ghost nodes that didn't get deleted completely and it's reference is accessed using edge traversal.
How much data do you have like this? I hope there will be very less data.
You can try to drop those bad references using "g.E('m4n-fug-bv9-39k').bothV().drop()". It will drop those nodes and edge as well.

Thanks,
Abhay



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Krishna Sailesh

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Jun 5, 2020, 10:49:56 AM6/5/20
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Hi Abhay,

i have some huge data like 10K vertices and 10K+ Edges

how do i get those wrong edge? as i use vertex traversal more than Edge traversal.


Thanks
Krishna Jalla
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