Details
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Improvement
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Status: Open
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Major
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Resolution: Unresolved
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JCR Resource 3.0.22
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None
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None
Description
I was performance testing our application. There is a specific part of the code where we have a set of ~500 resources and we sort them based on a few properties of the resources. Multiple properties are used (which results in multiple calls to getValueMap). The sorting is done using a comparator, so the logic that determines the order is accessed numerous times.
We've seen quite a decrease in performance when doing this with Resources that are of type JcrNodeResource. Turns out that the result of getValueMap (or adaptTo((Value)Map.class)) is not cached.
As you can see in the adaptTo()-method implementation: https://github.com/apache/sling-org-apache-sling-jcr-resource/blob/master/src/main/java/org/apache/sling/jcr/resource/internal/helper/jcr/JcrNodeResource.java#L136 this call bypasses the AdapterFactory framework and also bypasses any caching that happens over there.
What's even more unfortunate, is that JcrValueMap is implementing caching via https://github.com/apache/sling-org-apache-sling-jcr-resource/blob/6e13f4d315ddf2804d2e16c55faee18e805b618e/src/main/java/org/apache/sling/jcr/resource/internal/JcrValueMap.java#L49 . That caching is not leveraged properly, because every call to getValueMap returns a new JcrValueMap, instead of reusing a previously created one.
One change that can be done is maybe converting the logic inside the adaptTo()-method to a dedicated AdapterFactory implementation, so that caching is done by default?