[
https://issues.apache.org/jira/browse/TINKERPOP-1529?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15665444#comment-15665444
]
ASF GitHub Bot commented on TINKERPOP-1529:
-------------------------------------------
Github user dkuppitz commented on the issue:
https://github.com/apache/tinkerpop/pull/485
Here's an example that shows how it produces the expected result and still
tries to use `barrier()`'s as often as possible:
```
gremlin> g = TinkerFactory.createModern().traversal()
==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard]
gremlin> g.V().store("a").both().sideEffect(select("a").sideEffect {println
"Expect Intermediate: " + it.get()}).barrier().
......1> out().out().sideEffect(select("a").sideEffect {println "Expect
Final: " + it.get()})
Expect Intermediate: [v[1]]
Expect Intermediate: [v[1]]
Expect Intermediate: [v[1]]
Expect Intermediate: [v[1], v[2]]
Expect Intermediate: [v[1], v[2], v[3]]
Expect Intermediate: [v[1], v[2], v[3]]
Expect Intermediate: [v[1], v[2], v[3]]
Expect Intermediate: [v[1], v[2], v[3], v[4]]
Expect Intermediate: [v[1], v[2], v[3], v[4]]
Expect Intermediate: [v[1], v[2], v[3], v[4]]
Expect Intermediate: [v[1], v[2], v[3], v[4], v[5]]
Expect Intermediate: [v[1], v[2], v[3], v[4], v[5], v[6]]
Expect Final: [v[1], v[2], v[3], v[4], v[5], v[6]]
==>v[5]
==>v[5]
==>v[5]
Expect Final: [v[1], v[2], v[3], v[4], v[5], v[6]]
==>v[3]
==>v[3]
==>v[3]
gremlin> g.V().store("a").both().sideEffect(select("a").sideEffect {println
"Expect Intermediate: " + it.get()}).barrier().
......1> out().out().sideEffect(select("a").sideEffect {println "Expect
Final: " + it.get()}).explain()
==>Traversal Explanation
===========================================================================================================================================================================================================================================
Original Traversal [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
ConnectiveStrategy [D] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
MatchPredicateStrategy [O] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
InlineFilterStrategy [O] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
IncidentToAdjacentStrategy [O] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
AdjacentToIncidentStrategy [O] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
FilterRankingStrategy [O] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
RangeByIsCountStrategy [O] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
RepeatUnrollStrategy [O] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
PathRetractionStrategy [O] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
VertexStep(OUT,vertex)
,
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)])]
LazyBarrierStrategy [O] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
NoOpBarrierStep(2500),
VertexStep(OUT,vertex),
NoOpBarrierStep(2500), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)])]
TinkerGraphCountStrategy [P] [GraphStep(vertex,[]), StoreStep(a),
VertexStep(BOTH,vertex), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)]), NoOpBarrierStep, VertexStep(OUT,vertex),
NoOpBarrierStep(2500),
VertexStep(OUT,vertex),
NoOpBarrierStep(2500), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)])]
TinkerGraphStepStrategy [P] [TinkerGraphStep(vertex,[]),
StoreStep(a), VertexStep(BOTH,vertex),
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)]),
NoOpBarrierStep, VertexStep(OUT,vertex), NoOpBarrierStep(
2500), VertexStep(OUT,vertex),
NoOpBarrierStep(2500), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)])]
ProfileStrategy [F] [TinkerGraphStep(vertex,[]),
StoreStep(a), VertexStep(BOTH,vertex),
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)]),
NoOpBarrierStep, VertexStep(OUT,vertex), NoOpBarrierStep(
2500), VertexStep(OUT,vertex),
NoOpBarrierStep(2500), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)])]
StandardVerificationStrategy [V] [TinkerGraphStep(vertex,[]),
StoreStep(a), VertexStep(BOTH,vertex),
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)]),
NoOpBarrierStep, VertexStep(OUT,vertex), NoOpBarrierStep(
2500), VertexStep(OUT,vertex),
NoOpBarrierStep(2500), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)])]
Final Traversal [TinkerGraphStep(vertex,[]),
StoreStep(a), VertexStep(BOTH,vertex),
TraversalSideEffectStep([SelectOneStep(a), LambdaSideEffectStep(lambda)]),
NoOpBarrierStep, VertexStep(OUT,vertex), NoOpBarrierStep(
2500), VertexStep(OUT,vertex),
NoOpBarrierStep(2500), TraversalSideEffectStep([SelectOneStep(a),
LambdaSideEffectStep(lambda)])]
```
> LazyBarrierStrategy is too agressive
> ------------------------------------
>
> Key: TINKERPOP-1529
> URL: https://issues.apache.org/jira/browse/TINKERPOP-1529
> Project: TinkerPop
> Issue Type: Bug
> Components: process
> Affects Versions: 3.2.3
> Reporter: Daniel Kuppitz
> Assignee: Daniel Kuppitz
>
> There are scenarios where {{LazyBarrierStrategy}} changes the semantics of a
> traversal:
> {noformat}
> gremlin> g = TinkerFactory.createModern().traversal()
> ==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard]
> gremlin> g.V().store("a").out().select("a")
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> {noformat}
> This is actually not the result of {{store()}}, this is {{aggregate()}}. The
> expected result for {{store()}} would be:
> {noformat}
> ==>[v[1]]
> ==>[v[1]]
> ==>[v[1]]
> ==>[v[1],v[2],v[3],v[4]]
> ==>[v[1],v[2],v[3],v[4]]
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> {noformat}
> Another issue, which should probably go into another ticket, is this:
> {noformat}
> gremlin>
> g.withoutStrategies(LazyBarrierStrategy).V().store("a").out().select("a")
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> {noformat}
> That's it, the console is hanging at this point. Looks like
> {{PathRetractionStrategy}} is the remaining troublemaker. With both
> strategies excluded, we get the expected result:
> {noformat}
> gremlin> g.withoutStrategies(LazyBarrierStrategy,
> PathRetractionStrategy).V().store("a").out().select("a")
> ==>[v[1]]
> ==>[v[1]]
> ==>[v[1]]
> ==>[v[1],v[2],v[3],v[4]]
> ==>[v[1],v[2],v[3],v[4]]
> ==>[v[1],v[2],v[3],v[4],v[5],v[6]]
> {noformat}
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