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Posted to oak-issues@jackrabbit.apache.org by "Chetan Mehrotra (JIRA)" <ji...@apache.org> on 2015/03/03 12:15:04 UTC
[jira] [Created] (OAK-2568) Ignore redundant IS NOT NULL
constraints
Chetan Mehrotra created OAK-2568:
------------------------------------
Summary: Ignore redundant IS NOT NULL constraints
Key: OAK-2568
URL: https://issues.apache.org/jira/browse/OAK-2568
Project: Jackrabbit Oak
Issue Type: Improvement
Components: oak-lucene
Reporter: Chetan Mehrotra
Assignee: Chetan Mehrotra
Fix For: 1.0.12
Query like below at times take quite a time to evaluate with LucenePropertyIndex
{code}
SELECT * FROM [nt:unstructured] as content WHERE ISDESCENDANTNODE('/content/dam/en/us')
and(
content.[tags] = 'Products:A'
or content.[tags] = 'Products:A/B'
or content.[tags] = 'Products:A/B'
or content.[tags] = 'Products:A'
)
and(
content.[tags] = 'DocTypes:A'
or content.[tags] = 'DocTypes:B'
or content.[tags] = 'DocTypes:C'
or content.[tags] = 'ProblemType:A'
)
and(
content.[hasRendition] IS NULL
or content.[hasRendition] = 'false'
)
{code}
Now above SQL query translates to following plan
*Plan on 1.0 branch*
{noformat}
[nt:unstructured] as [content] /* lucene:test1(/oak:index/test1) +tags:[* TO *] +(tags:Products:A tags:Products:A/B tags:Products:A/B tags:Products:A) +(tags:DocTypes:A tags:DocTypes:B tags:DocTypes:C tags:ProblemType:A)
where ((((isdescendantnode([content], [/content/dam/en/us]))
and ([content].[tags] is not null))
and ([content].[tags] in(cast('Products:A' as string), cast('Products:A/B' as string), cast('Products:A/B' as string), cast('Products:A' as string))))
and ([content].[tags] is not null))
and ([content].[tags] in(cast('DocTypes:A' as string), cast('DocTypes:B' as string), cast('DocTypes:C' as string), cast('ProblemType:A' as string))) */
{noformat}
Note the extra property restriction of not null which translates in Lucene to {{+tags:\[* TO *\]}}
*Plan on trunk*
{noformat}
[nt:unstructured] as [content] /* lucene:test1(/oak:index/test1) +(tags:Products:A tags:Products:A/B) +(tags:DocTypes:A tags:DocTypes:B tags:DocTypes:C tags:ProblemType:A)
where (isdescendantnode([content], [/content/dam/en/us]))
and ([content].[tags] in('Products:A', 'Products:A/B'))
and ([content].[tags] in('DocTypes:A', 'DocTypes:B', 'DocTypes:C', 'ProblemType:A')) */
{noformat}
{color:brown}This one does not have the extra not null constraint{color}
The query was performing slower on Lucene because the property existence query i.e. not null constraint is currently evaluated as a range query in Lucene which looks like is bit expensive to evaluate.
Now as shown above it appears that on trunk the QueryEngine performs such an optimization on its own (possibly done with [1610723|http://svn.apache.org/viewvc/jackrabbit/oak/trunk/oak-core/src/main/java/org/apache/jackrabbit/oak/query/ast/OrImpl.java?r1=1610723&r2=1610722&pathrev=1610723] as part of OAK-1965. This change is not present in branch.
Given that change in OAK-1965 was quite big it would be better to perform such optimization in {{LucenePropertyIndex}} itself
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