[jira] [Commented] (JENA-577) TDB detects attempt to reassign a variable.

["ASF subversion and git services (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JENA-577?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13807984#comment-13807984 ] 

ASF subversion and git services commented on JENA-577:
------------------------------------------------------

Commit 1536710 from [~andy.seaborne] in branch 'jena/trunk'
[ https://svn.apache.org/r1536710 ]

JENA-577 : Rewrite merging bindings when an OpProject is in the middel of an execution (sub-SELECT).

> TDB detects attempt to reassign a variable.
> -------------------------------------------
>
>                 Key: JENA-577
>                 URL: https://issues.apache.org/jira/browse/JENA-577
>             Project: Apache Jena
>          Issue Type: Bug
>          Components: ARQ, TDB
>    Affects Versions: Jena 2.11.0
>            Reporter: Andy Seaborne
>            Assignee: Andy Seaborne
>         Attachments: DevMain.java
>
>
> With TDB, but not with a general in-memory dataset, a query of the form:
> {noformat}
> PREFIX  :     <http://example/>
> SELECT  *
> WHERE
>   { ?x :p 123
>     { SELECT  ?x
>       WHERE
>         { ?x :p ?o }
>     }
>   }
> {noformat}
> (key feature: projection from the subsquery)
> causes
> {noformat}
> 20:24:32 ERROR QueryIteratorCloseable    :: QueryFatalException
> com.hp.hpl.jena.sparql.ARQInternalErrorException: Attempt to reassign '?x' from '<http://example/x>' to '<http://example/x>'
> 	at com.hp.hpl.jena.sparql.engine.binding.BindingHashMap.checkAdd(BindingHashMap.java:111)
> 	at com.hp.hpl.jena.sparql.engine.binding.BindingHashMap.add(BindingHashMap.java:92)
> 	at com.hp.hpl.jena.sparql.engine.binding.BindingFactory.materialize(BindingFactory.java:60)
> 	at com.hp.hpl.jena.tdb.solver.QueryEngineTDB$QueryIteratorMaterializeBinding.moveToNextBinding(QueryEngineTDB.java:132)
> 	at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.nextBinding(QueryIteratorBase.java:154)
> {noformat}
> Looking at the optimized algebra, TDB is correct.



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