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https://issues.apache.org/jira/browse/TINKERPOP-2095?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daniel Kuppitz updated TINKERPOP-2095:
--------------------------------------
Description:
{{GroupStep}} looks for a {{Barrier}} step to determine the reducing
bi-operator. This is wrong and I'm really surprised that this has never been
spotted before.
{noformat}
gremlin>
g.V().hasLabel('person').as('p').out('created').group().by('name').by(select('p').values('age').sum())
java.lang.Long cannot be cast to
org.apache.tinkerpop.gremlin.process.traversal.traverser.util.TraverserSet
Type ':help' or ':h' for help.
Display stack trace? [yN]
{noformat}
In the query above the first barrier step is a {{NoOpBarrier}} step (added by
{{PathRetractionStrategy}}). This step obviously has no reducing bi-operator.
What we really want to do is look for the first barrier step that is not a
{{LocalBarrier}} step.
was:
{{GroupStep}} looks for {{Barrier}} step to determine the reducing bi-operator.
This is wrong and I'm really surprised that this has never been spotted before.
{noformat}
gremlin>
g.V().hasLabel('person').as('p').out('created').group().by('name').by(select('p').values('age').sum())
java.lang.Long cannot be cast to
org.apache.tinkerpop.gremlin.process.traversal.traverser.util.TraverserSet
Type ':help' or ':h' for help.
Display stack trace? [yN]
{noformat}
In the query above the first barrier step is a {{NoOpBarrier}} step (added by
{{PathRetractionStrategy}}). This step obviously has no reducing bi-operator.
What we really want to do is look for the first reducing barrier step.
> GroupStep looks for irrelevant barrier steps
> --------------------------------------------
>
> Key: TINKERPOP-2095
> URL: https://issues.apache.org/jira/browse/TINKERPOP-2095
> Project: TinkerPop
> Issue Type: Bug
> Components: process
> Affects Versions: 3.3.4
> Reporter: Daniel Kuppitz
> Assignee: Daniel Kuppitz
> Priority: Major
>
> {{GroupStep}} looks for a {{Barrier}} step to determine the reducing
> bi-operator. This is wrong and I'm really surprised that this has never been
> spotted before.
> {noformat}
> gremlin>
> g.V().hasLabel('person').as('p').out('created').group().by('name').by(select('p').values('age').sum())
> java.lang.Long cannot be cast to
> org.apache.tinkerpop.gremlin.process.traversal.traverser.util.TraverserSet
> Type ':help' or ':h' for help.
> Display stack trace? [yN]
> {noformat}
> In the query above the first barrier step is a {{NoOpBarrier}} step (added by
> {{PathRetractionStrategy}}). This step obviously has no reducing bi-operator.
> What we really want to do is look for the first barrier step that is not a
> {{LocalBarrier}} step.
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