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From "Dirk Rudolph (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (OAK-7109) rep:facet returns wrong results for complex queries
Date Fri, 19 Jan 2018 14:01:00 GMT

    [ https://issues.apache.org/jira/browse/OAK-7109?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16332289#comment-16332289
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Dirk Rudolph commented on OAK-7109:
-----------------------------------

Thanks for the response. Regarding 1) see https://issues.apache.org/jira/browse/OAK-7109?focusedCommentId=16309376&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16309376

Optimisation does the following at the moment:

A and (B or not(C and D)) => (A and B) or (A and not(C and D))

To achieve an optimisation where the result is a DNF, which can then be split in UNIONS of exclusively
conjunctions, another step needs to happen before the current optimisation - NNF (moving all negation
down the tree of statements)

A and (B or not(C or D)) => A and (B or not(C) or not(B)) => (A and B) or (A and
not(C)) or (A and not(B)) 

Not sure if the index supports not() but if it does, the UNION of the query above (3) queries
would give exact facets which simply need to be deduplicated. 

 

> rep:facet returns wrong results for complex queries
> ---------------------------------------------------
>
>                 Key: OAK-7109
>                 URL: https://issues.apache.org/jira/browse/OAK-7109
>             Project: Jackrabbit Oak
>          Issue Type: Bug
>          Components: lucene
>    Affects Versions: 1.6.7
>            Reporter: Dirk Rudolph
>            Priority: Major
>              Labels: facet
>         Attachments: facetsInMultipleRoots.patch, restrictionPropagationTest.patch
>
>
> eComplex queries in that case are queries, which are passed to lucene not containing
all original constraints. For example queries with multiple path restrictions like:
> {code}
> select [rep:facet(simple/tags)] from [nt:base] as a where contains(a.[*], 'ipsum') and
(isdescendantnode(a,'/content1') or isdescendantnode(a,'/content2'))
> {code}
> In that particular case the index planer gives ":fulltext:ipsum" to lucene even though
the index supports evaluating path constraints. 
> As counting the facets happens on the raw result of lucene, the returned facets are incorrect.
For example having the following content 
> {code}
> /content1/test/foo
>  + text = lorem ipsum
>  - simple/
>   + tags = tag1, tag2
> /content2/test/bar
>  + text = lorem ipsum
>  - simple/
>   + tags = tag1, tag2
> /content3/test/bar
>  + text = lorem ipsum
>  - simple/
>    + tags = tag1, tag2
> {code}
> the expected result for the dimensions of simple/tags and the query above is 
> - tag1: 2
> - tag2: 2
> as the result set is 2 results long and all documents are equal. The actual result set
is 
> - tag1: 3
> - tag2: 3
> as the path constraint is not handled by lucene.
> To workaround that the only solution that came to my mind is building the [disjunctive
normal form|https://en.wikipedia.org/wiki/Disjunctive_normal_form] of my complex query and
executing a query for each of the disjunctive statements. As this is expanding exponentially
its only a theoretical solution, nothing for production. 



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