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https://issues.apache.org/jira/browse/JENA-1877?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17073126#comment-17073126
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Andy Seaborne commented on JENA-1877:
-------------------------------------
Simple example:
{code}
SELECT (bnode("A") as ?X) (bnode("A") as ?Y)
WHERE { }
{code}
The same string.
The query is the same as:
{code}
SELECT ?X ?Y
WHERE {
BIND (bnode("A") as ?X)
BIND (bnode("A") as ?Y)
}
{code}
and each {{BIND}} creates a new row when it adds it variable/value binding.
> Wrong results for non-optimized query
> -------------------------------------
>
> Key: JENA-1877
> URL: https://issues.apache.org/jira/browse/JENA-1877
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: Jena 3.14.0
> Reporter: Jeremy Coulon
> Priority: Major
> Attachments: bnode01.rq, data.ttl
>
>
> I noticed that the attached query gives correct results with:
> {noformat}
> ./bin/arq --data=data.ttl --query=bnode01.rq --explain --optimize=on
> {noformat}
> while it gives wrong results with:
> {noformat}
> ./bin/arq --data=data.ttl --query=bnode01.rq --explain
> --optimize=off{noformat}
> Without optimization, ARQ algebra has 2 different 'extend' op with
> 'bnode(?s)' expression.
> With optimization, ARQ algebra merges these ops into a single op 'extend'.
>
> I tried debugging and I think that 'E_BNode.evalSpecial()' takes the same
> 'binding' object for each call in optimized mode but different 'binding'
> objects for non-optimized mode. This function relies on reference-equality.
>
> [^data.ttl]
> [^bnode01.rq]
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