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https://issues.apache.org/jira/browse/CLEREZZA-643?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13136027#comment-13136027
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Rupert Westenthaler commented on CLEREZZA-643:
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I completely agree with this assessment.
In case the decision would be to not apply this patch I want to remind you that
independently of this the current implementation does use platform encoding
instead of UTF-8 for reading and writing. This need to be fixed regardless of
the algorithm used to serialize the Graph.
related to:
> - As I understand the rdf-json specification, sorting of output is not
> required, only grouping by subject and predicate.
> Therefore I don't think the more expensive subject-predicate sort (that you
> commented out but still included) is
> necessary. Or am I missing something? Can this part be safely removed?
Thats correct. I just was keeping that to provide some context of the different
variants I tried.
> Weak Performance of "application/json+rdf" serializer on big
> TripleCollections and Serialzer/Parser using Platform encoding instead of
> UTF-8
> --------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: CLEREZZA-643
> URL: https://issues.apache.org/jira/browse/CLEREZZA-643
> Project: Clerezza
> Issue Type: Improvement
> Reporter: Rupert Westenthaler
> Assignee: Daniel Spicar
> Attachments: rdf.rdfjson-arrays.sort_based_serializer_and_UTF-8.patch
>
>
> Both the "application/json+rdf" serializer and parser use platform specific
> encodings instead of UTF-8.
> In addition the serializer suffers from very poor performance on big graphs
> (at least when using SimpleMGrpah)
> After some digging in the Code I came to the conclusion that this is because
> of the use of multiple TripleCollection.filter(..) calls fist to filter all
> predicates for an subject and than all objects for each subject/predicate
> combination. A trying to serialize a graph with 50k triples ended in several
> minutes 100% CPU.
> With the next comment I will provide a patch with an implementation based on
> a sorted array of the triples. With this method one can serialize graphs with
> 100k in about 1sec. This patch also changes encoding to UTF-8.
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