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https://issues.apache.org/jira/browse/JENA-681?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13975670#comment-13975670
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ASF subversion and git services commented on JENA-681:
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Commit 1588912 from [~andy.seaborne] in branch 'jena/trunk'
[ https://svn.apache.org/r1588912 ]

JENA-681 : Put back the original filter placement code as 
TransformFilterPlacementConservative.
Alternative filter placement transformation.
Not used by default.

> Allow the old less aggressive filter placement behaviour to be optionally 
> used in place of the newer more aggressive behaviour
> ------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: JENA-681
>                 URL: https://issues.apache.org/jira/browse/JENA-681
>             Project: Apache Jena
>          Issue Type: Improvement
>          Components: ARQ, Optimizer
>    Affects Versions: Jena 2.11.1
>            Reporter: Rob Vesse
>            Assignee: Rob Vesse
>             Fix For: Jena 2.11.2
>
>         Attachments: JENA-681.patch
>
>
> In investigating some optimiser caused performance regression issues that 
> occurred after we upgraded at Cray to using 2.11.1 it was discovered that the 
> new filter pushing was too aggressive for our backend in how it broke up 
> BGPs/quadpatterns
> Ideally we would like to use the filter placement mode where we place filters 
> without breaking BGPs but as discussed in JENA-627 and JENA-628 (as well as 
> other related issues) this behaviour is broken in the 2.11.1 release and 
> indeed the specific problem query did get horribly mangled with this mode 
> enabled.
> I have been able to verify that the relevant fixes for those bugs means the 
> affected query does now get optimised appropriately using the latest trunk 
> code and I've added a sanitised version of the relevant query to the test 
> cases.
> *However* it would be nice if we had the option of switching back on the more 
> conservative pre 2.11.1 filter placement behaviour if we desired.  This is 
> preserved in {{TransformFilterPlacement_Old}} and currently noted in comments 
> that it will be removed in future.
> What I propose to do instead is to rename this to 
> {{TransformFilterPlacementConservative}} and add an associated 
> {{optFilterPlacementConservative}} flag which when explicitly enabled will 
> use the old filter placement behaviour rather than the newer more aggressive 
> filter placement behaviour.
> I'll attach a proposed patch for this later today



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