[teiid-issues] [JBoss JIRA] (TEIID-2381) Expanded source hint support

[Mark Addleman (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-2381?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12764763#comment-12764763 ] 

Mark Addleman commented on TEIID-2381:
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Yes, this use case is entirely about your last bullet. 

Here are my thoughts on your list of issues:  
If I understand the first bullet correctly, it's about allowing hints to be placed elsewhere in a command and, presumably, they'd be available from the appropriate language object.  Something like:
SELECT a, /*+ sh:'source' column hint */ b FROM /*+ sh:'source' t

Other than disambiguating the current syntax as a hint that properly belongs on the Query object rather than the first column object, I think it's separate from the other issues.  

Personally, I like this approach a lot and seems to offer a great deal of flexibility.  To your second point, I can't imagine a more expressive solution that's as easy to comprehend.  Did you have something in mind?

I don't understand your third point or I'm confusing your first and third points.  Maybe provide an example illustrating this?

As for your fourth point, if hints are expressed like the example I gave above, I think if the query objects that may contain hints are carefully chosen, the propagation rules can be straightforward (although I'm probably overlooking some complexities) but I do see a need to change the translator API to retrieve hints.  I would simply add public Iteratable<String> getSourceHints() to the API.  I would make the translator responsible for deciding which hints are appropriate.


                
> Expanded source hint support
> ----------------------------
>
>                 Key: TEIID-2381
>                 URL: https://issues.jboss.org/browse/TEIID-2381
>             Project: Teiid
>          Issue Type: Enhancement
>          Components: Query Engine
>            Reporter: Steven Hawkins
>            Assignee: Steven Hawkins
>         Attachments: HintsExecutionFactory.java, RandomExecutionFactory.java, RandomNumberStoredProcedureExecution.java, SysviewHintsExecutionTest.java
>
>
> We currently look at the source hint in only the root user query (not in subqueries nor the with clause) and only consider it in a very narrow set of circumstances when it's used in a view.

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