Corrupted data & index after simultaneous vertex delete and indexed property update

[jjurowicz]

[similar to #993]
Checked on janusgraph 0.2.0 and 0.3.0 (snapshot from 04.April.2018) on cassandra 3.11.1
This problem occurs on our environment, where by default we have 30 separate simultaneous connections to single janusgraph instance.
I was able to reduce the problem to simple reproducible scenario:

First, you need to connect to db (best empty) from two gremlin consoles (A and B) and proceed as follows:

on any gremlin console:

mgmt = g.openManagement()
mgmt.makePropertyKey("name").dataType(String.class).cardinality(Cardinality.SINGLE).make()
idx = mgmt.buildIndex("nameIndex", Vertex.class)
idx.addKey(mgmt.getPropertyKey("name")).buildCompositeIndex()
mgmt.commit()

gremlin console A)

g.addVertex("name", "A")
g.tx().commit()
v = g.traversal().V().has("name", "A").next()

gremlin console B)

g.traversal().V().has("name", "A").drop()
g.tx().commit()

gremlin console A)

v.property("name", "C")
g.tx().commit()

AFTER this check corrupted data on any console:
this will return "zombie" vertex
g.traversal().V().has("name", "C")
that is not on all vertices list:
g.traversal().V()