Index corruption after reindexing vertex-centric indices with direction 'BOTH'


Shiva Krishnan <shivain...@...>
 

I have noticed a corruption in index after reindexing vertex-centric indices with direction 'BOTH'.

Issue : A self-link is getting added to every vertex after reindexing.

To demonstrate this, I have taken a very small graph consists of two vertices (A & B) and one bidirectional edge connecting the two.

Also I have created an vertex-centric index.

gremlin > edgeLabel = mgmt.getEdgeLabel("link");
gremlin > assocKind= mgmt.getPropertyKey("assocKind")
gremlin > mgmt.buildEdgeIndex(edgeLabel, "myVertexCentricIndex", Direction.BOTH, assocKind);

Please note i have given the direction BOTH for the index.

I tried querying for the edge using the vertex centric index.
expectation :  [A -> B] ==> one outE in vertex A and one inE in vertex B.

//Gremlin output:
gremlin> g.V().has('objId' , 'A').inE().hasLabel('link').has('assocKind',16)
//no IN edges to vertex A  Correct

gremlin> g.V().has('objId' , 'A').outE().hasLabel('link').has('assocKind',16)
==>e[4e1f-b6g-1bit-1pqw][14488-link->80024]   Correct

Now I ran a reindex for the index.

// 'index' is the vertex centric index which is created above
gremlin> m.updateIndex(index, SchemaAction.REINDEX).get()
==>org.janusgraph.diskstorage.keycolumnvalue.scan.StandardScanMetrics@28babeca
gremlin> m.commit()

After this when I try to execute the same query which is used above, I have noticed an unexpected self link in vertex A

gremlin> g.V().has('_objId','A').inE().hasLabel('link').has('assocKind',16)
==>e[4e1f-b6g-1bit-b6g][14488-link->14488] Wrong

gremlin> g.V().has('_objId','A').bothE().hasLabel('link').has('assocKind',16)
==>e[4e1f-b6g-1bit-1pqw][14488-link->80024]
==>e[4e1f-b6g-1bit-b6g][14488-link->14488] Unexpected Link

Though the primary representation of the graph is not affected.

gremlin> g.E()
14:17:51 WARN  org.janusgraph.graphdb.transaction.StandardJanusGraphTx  - Query requires iterating over all vertices [()]. For better performance, use indexes
==>e[4e1f-b6g-1bit-1pqw][14488-link->80024] Correct

After reindexing, the vertex centric edges with direction BOTH is getting corrupted.

I'm using Janus 0.2.3 for my testing.

Could anyone please help me on this issue.

Thanks
Shiva

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