Ok apologies. I thought I spotted the difference and simplified the
gremlin too much to highlight what I thought I saw. The above mentioned
queries are returning the same result in Sqlg as TinkerGraph.
Here is what is not working.
final TinkerGraph g = TinkerFactory.createModern();
GraphTraversal<Vertex, Map<Vertex, Collection<Vertex>>>
traversal = g.traversal()
.V().as("a")
.repeat(both()).times(3).emit().as("b")
.<Vertex, Collection<Vertex>>group().by(select("a"));
printTraversalForm(traversal);
while (traversal.hasNext()) {
Map<Vertex, Collection<Vertex>> vertexMap = traversal.next();
for (Vertex vertex : vertexMap.keySet()) {
Collection<Vertex> coll = vertexMap.get(vertex);
System.out.println("key: " + vertex.value("name") + ",
value: " + coll.size());
}
}
For this Sqlg has the same result as TinkerGraph.
TinkerGraph
post-strategy:[TinkerGraphStep(vertex,[])@[a],
RepeatStep([VertexStep(BOTH,vertex),
RepeatEndStep],until(loops(3)),emit(true))@[b],
GroupStep([SelectOneStep(a), NoOpBarrierStep(2500)],[FoldStep])]
Sqlg
post-strategy:[SqlgGraphStepCompiled(vertex,[])@[sqlgPathFakeLabel],
GroupStep([SelectOneStep(a)],[FoldStep])]
key: marko, value: 27
key: vadas, value: 11
key: lop, value: 27
key: josh, value: 27
key: ripple, value: 11
key: peter, value: 11
Adding in the extra by()
final TinkerGraph g = TinkerFactory.createModern();
GraphTraversal<Vertex, Map<Vertex, Collection<Vertex>>>
traversal = g.traversal()
.V().as("a")
.repeat(both()).times(3).emit().as("b")
.<Vertex, Collection<Vertex>>group().by(select("a"))
.by(select("b").dedup().order().by(T.id).fold());
printTraversalForm(traversal);
while (traversal.hasNext()) {
Map<Vertex, Collection<Vertex>> vertexMap = traversal.next();
for (Vertex vertex : vertexMap.keySet()) {
Collection<Vertex> coll = vertexMap.get(vertex);
System.out.println("key: " + vertex.value("name") + ",
value: " + coll.size());
}
}
TinkerGraph prints
post-strategy:[TinkerGraphStep(vertex,[])@[a],
RepeatStep([VertexStep(BOTH,vertex),
RepeatEndStep],until(loops(3)),emit(true))@[b],
GroupStep([SelectOneStep(a), NoOpBarrierStep(2500)],[SelectOneStep(b),
DedupGlobalStep, OrderGlobalStep([[id, incr]]), FoldStep])]
key: marko, value: 6
key: vadas, value: 6
key: lop, value: 6
key: josh, value: 6
key: ripple, value: 6
key: peter, value: 6
and Sqlg
post-strategy:[SqlgGraphStepCompiled(vertex,[])@[sqlgPathFakeLabel],
GroupStep([SelectOneStep(a)],[SelectOneStep(b), DedupGlobalStep,
OrderGlobalStep([[id, incr]]), FoldStep])]
key: marko, value: 0
key: ripple, value: 0
key: peter, value: 0
key: lop, value: 0
key: josh, value: 0
key: vadas, value: 0
The difference being the NoOpBarrierStep but I am not sure if that is
the culprit or not.
Thanks
Pieter
On 24/10/2016 21:31, Marko Rodriguez wrote:
> Hi Pieter,
>
> What are the two answers --- TinkerGraph and Sqlg for the respective test
> traversal?
>
> (I suspect the test is bad because group() pushes traversers through with
> bulks and all so the test might just add to a collection without adding
> respecting bulks. Probably should change that test regardless to do like a
> count or something instead).
>
> Marko.
>
> http://markorodriguez.com
>
>
>
>> On Oct 24, 2016, at 12:57 PM, pieter-gmail <[email protected]> wrote:
>>
>> Hi,
>>
>> This is on 3.2.3
>>
>> I have been investigating why
>> `DedupTest.g_V_asXaX_repeatXbothX_timesX3X_emit_asXbX_group_byXselectXaXX_byXselectXbX_dedup_order_byXidX_foldX_selectXvaluesX_unfold_dedup`
>> fails on Sqlg. It is a fairly recently added test.
>>
>> My investigation so far has narrowed the problem to the
>> `PathRetractionStrategy`
>>
>> On the modern graph,
>>
>> GraphTraversal<Vertex, Map<Vertex, Collection<Vertex>>>
>> traversal = g.traversal()
>> .V().as("a")
>> .out().as("b")
>> .<Vertex, Collection<Vertex>>group().by(select("a"))
>> .by(select("b"));
>> printTraversalForm(traversal);
>>
>> Outputs the following on TinkerGraph
>>
>> pre-strategy:[GraphStep(vertex,[])@[a], VertexStep(OUT,vertex)@[b],
>> GroupStep([SelectOneStep(a)],[SelectOneStep(b)])]
>> post-strategy:[TinkerGraphStep(vertex,[])@[a],
>> VertexStep(OUT,vertex)@[b], GroupStep([SelectOneStep(a),
>> NoOpBarrierStep(2500)],[SelectOneStep(b), NoOpBarrierStep(2500)])]
>>
>> And on Sqlg
>> pre-strategy:[GraphStep(vertex,[])@[a], VertexStep(OUT,vertex)@[b],
>> GroupStep([SelectOneStep(a)],[SelectOneStep(b)])]
>> post-strategy:[SqlgGraphStepCompiled(vertex,[])@[b],
>> GroupStep([SelectOneStep(a)],[SelectOneStep(b)])]
>>
>> The difference being that Sqlg does not have the `NoOpBarrierStep` inserted.
>>
>> For TinkerGraph the `NoOpBarrierStep` is being inserted in the
>> `PathRetractionStrategy` on line 113
>> However this does not happen for Sqlg as Sqlg's GraphStep has
>> `TraverRequirement.PATH` as a requirement which prevents
>> `PathRetractionStrategy` from doing what it does.
>>
>> Is this a bug of sorts? Should Sqlg be adding in the `NoOpBarrierStep`?
>>
>> Thanks
>> Pieter
