[jira] [Resolved] (SLING-4596) Performance: Consider optimizing JcrItemResource#getParent and getChild

["Carsten Ziegeler (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SLING-4596?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Carsten Ziegeler resolved SLING-4596.
-------------------------------------
    Resolution: Won't Fix

We'll handle this as part of SLING-4750

> Performance: Consider optimizing JcrItemResource#getParent and getChild
> -----------------------------------------------------------------------
>
>                 Key: SLING-4596
>                 URL: https://issues.apache.org/jira/browse/SLING-4596
>             Project: Sling
>          Issue Type: Improvement
>          Components: JCR, ResourceResolver
>    Affects Versions: JCR Resource 2.5.0
>            Reporter: Joel Richard
>            Priority: Critical
>              Labels: performance
>         Attachments: JcrNodeResource_getParent.patch, SLING-4596_experimental.patch
>
>
> I have noticed that on some "resource intensive" pages up to 24% of the rendering time is spent in AbstractResource.getParent. One of the main reasons for this is because the ParentHidingHandler traverses for each resource to the root (see SLING-4568).
> getParent is not just called often, but is also about 10 times slower than jcrNode.getParent() which has the following reasons:
> - itemExists is called unnecessary because JcrResourceProvider#createResource does not know that the path belongs to a parent of a node which has already been read. See also SLING-4585.
> - jcrSession.getItem (which is used to read parents in JcrResourceProvider#createResource) is about 3.5 times slower than jcrNode.getParent in Oak.
> - Some other overhead which cannot be avoided entirely.
> The situation could be improved with a getParent implementation which is specific to JcrNodeResource and uses getNode().getParent() directly to create a new JcrNodeResource. I have implemented such a method (see attached experimental patch) and it reduces the time for getParent from 24% to 5% on my test page.
> As discussed on the [mailing list|http://mail-archives.apache.org/mod_mbox/sling-dev/201504.mbox/%3C55266BB2.1050506%40apache.org%3E] this is not a good solution because the parent resource could be backed by another provider. An alternative approach would be to create a new resource provider interface which accepts the base resource (which is passed to resourceResolver.getResource), retrieves the node form it and uses it for a direct getParent/getNode call (see the linked mail for more information).



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