CODEWITHSUNDEEP
gremlinjanusgraphtinkerpop3gremlinpython
Sumit Kumar
Sumit Kumar

Reputation: 760

Why running same query for tinkergraph and janusgraph, produces different result?

I tried following query with Gremlin and Tinkerpop

gremlin> graph = TinkerGraph.open()
==>tinkergraph[vertices:0 edges:0]
gremlin> g = traversal().withEmbedded(graph)
==>graphtraversalsource[tinkergraph[vertices:0 edges:0], standard]
gremlin> v = g.addV().property('name','marko').property('name','marko a. rodriguez').next()
==>v[0]
gremlin> g.V(v).properties('name').count()
==>2
gremlin>

When I run same with Gremlin-Python and Janusgraph,recieves following.

>>> v = g.addV().property('name','marko').property('name','marko a. rodriguez').next()
>>> g.V(v).properties('name').count().next()
1

My question is, why I am receiving different result. In the first case the output is 2, but in second case the output is 1.

I have tried to run the following queries too to explore more, and find the following result.

With Gremlin and TinkerpopGraph

gremlin> g.V(v).values('name')
==>marko
==>marko a. rodriguez
gremlin>

With Gremlin-Python and JanusGraph

>>> g.V(v).values('name').next()
'marko a. rodriguez'

When I tried the following with gremlin and Janusgraph, it works

gremlin> v = g.addV().property(list,'p_name','marko').property(list,'p_name','marko a. rodriguez').next()
==>v[12344]
gremlin> g.V(v).properties('p_name').count()
==>0

But running the same results in gremlin-python gives me error.

>>> v = g.addV().property(list,'p_name','marko').property(list,'p_name','marko a. rodriguez').next()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/sumit/.local/lib/python3.9/site-packages/gremlin_python/process/traversal.py", line 88, in next
    return self.__next__()
  File "/home/sumit/.local/lib/python3.9/site-packages/gremlin_python/process/traversal.py", line 47, in __next__
    self.traversal_strategies.apply_strategies(self)
  File "/home/sumit/.local/lib/python3.9/site-packages/gremlin_python/process/traversal.py", line 548, in apply_strategies
    traversal_strategy.apply(traversal)
  File "/home/sumit/.local/lib/python3.9/site-packages/gremlin_python/driver/remote_connection.py", line 63, in apply
    remote_traversal = self.remote_connection.submit(traversal.bytecode)
  File "/home/sumit/.local/lib/python3.9/site-packages/gremlin_python/driver/driver_remote_connection.py", line 60, in submit
    results = result_set.all().result()
  File "/usr/lib/python3.9/concurrent/futures/_base.py", line 440, in result
    return self.__get_result()
  File "/usr/lib/python3.9/concurrent/futures/_base.py", line 389, in __get_result
    raise self._exception
  File "/home/sumit/.local/lib/python3.9/site-packages/gremlin_python/driver/resultset.py", line 90, in cb
    f.result()
  File "/usr/lib/python3.9/concurrent/futures/_base.py", line 433, in result
    return self.__get_result()
  File "/usr/lib/python3.9/concurrent/futures/_base.py", line 389, in __get_result
    raise self._exception
  File "/usr/lib/python3.9/concurrent/futures/thread.py", line 52, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/home/sumit/.local/lib/python3.9/site-packages/gremlin_python/driver/connection.py", line 83, in _receive
    status_code = self._protocol.data_received(data, self._results)
  File "/home/sumit/.local/lib/python3.9/site-packages/gremlin_python/driver/protocol.py", line 131, in data_received
    raise GremlinServerError(message['status'])
gremlin_python.driver.protocol.GremlinServerError: 599: null: .property(ArrayList, String, String)

599: null: .property(ArrayList, String, String)

Upvotes: 1

Views: 142

Answers (1)

Kelvin Lawrence
Kelvin Lawrence

Reputation: 14371

I believe what you are seeing is a special case condition with TinkerGraph where if you create two properties with the same key while creating the vertex as well, list cardinality is assumed. If you were to perform the same property additions on a vertex that already exists, single cardinality would be assumed and one would replace the other. For example:

gremlin> g.addV('xyz')
==>v[3]

gremlin> 
g.V().hasLabel('xyz').property('name','me').property('name','me2').valueMap()
==>[name:[me2]]

As to your Python error, list is a Python reserved word. Try using Cardinality.list

In general if your intent is to create a List or Set, be explicit with the cardinality value to ensure you get the expected results.

Upvotes: 1

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