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https://issues.apache.org/jira/browse/SLING-3301?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Carsten Ziegeler updated SLING-3301:
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    Assignee:     (was: Carsten Ziegeler)

> Add internal component for hierarchy queries
> --------------------------------------------
>
>                 Key: SLING-3301
>                 URL: https://issues.apache.org/jira/browse/SLING-3301
>             Project: Sling
>          Issue Type: Bug
>          Components: ResourceResolver
>    Affects Versions: Resource Resolver 1.0.6
>            Reporter: Alexander Klimetschek
>            Priority: Critical
>              Labels: Performance
>
> SLING-2457 fixed the ACL issue with super type lookups, but at the cost of 
> creating a new admin resource resolver for every super type lookup. If an 
> inheritance chain contains multiple super types (N), a single call can 
> trigger the creation of N admin sessions. Often this also happens for a 
> number of resources per request, depending on the application, so you might 
> end up creating many Jackrabbit JCR sessions per request. While creating a 
> resource resolver / session is cheap, having too many at the same time has a 
> big performance impact on the read performance due to increased concurrency 
> in the JCR repository layer.
> This affects:
> * ResourceUtil.isA()
> * Resource.isResourceType()
> * ResourceResolver.isResourceType()
> * implementation in ResourceResolverImpl.isResourceType() and 
> getParentResourceType() [1]
> A simple fix could be to cache a single admin resolver for the duration of 
> the resource resolver containing it and reusing it for subsequent 
> isResourceType() calls.
> Another improvement could also be to cache the isResourceType() lookups - if 
> this is a typical short-lived request resource resolver. Within a request 
> resource type hierarchies are unlikely to change and should probably be 
> stable (and with Jackrabbit Oak the session won't refresh anyway). The cache 
> would simply be a map of "resource type" => "is also this resource type", so 
> that the super lookups don't have to be done again and again. Often an 
> application might iterate over a tree of data and looking for the same 
> resource type again and again, so the hit rate for the cache will be high.
> [1] 
> https://svn.apache.org/viewvc/sling/trunk/bundles/resourceresolver/src/main/java/org/apache/sling/resourceresolver/impl/ResourceResolverImpl.java?revision=1537136&view=markup



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