[jira] [Updated] (JENA-384) Interaction of optimization (TransformFilterEquality) and initial binding

["Andy Seaborne (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/JENA-384?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andy Seaborne updated JENA-384:
-------------------------------

    Labels: ARQ optimizer  (was: ARQ)
    
> Interaction of optimization (TransformFilterEquality) and initial binding
> -------------------------------------------------------------------------
>
>                 Key: JENA-384
>                 URL: https://issues.apache.org/jira/browse/JENA-384
>             Project: Apache Jena
>          Issue Type: Bug
>    Affects Versions: ARQ 2.9.4, Jena 2.10.0
>            Reporter: Andy Seaborne
>              Labels: ARQ, optimizer
>         Attachments: ReportSubstitueOptimize.java
>
>
> substitution is normally done after optimization so that it preserves the semantics in case of complex optional situations. 
> The equality filter optimization eliminates code that can't generate a solution (the variable is unbound in the subexpression)
> This can be unexpected but it's neither clearly right or clearly wrong. The semantics of initial binding need clarifying; 
>    either 
>       pure substitution semantics, with the substitution applied before optimization
>    or 
>       VALUES semantics (join with a data table) in which case elimination of redundant pattern matching is correct.
> In the example, it's only an issue with URIs (reason?) but the general point remains.

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