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https://issues.apache.org/jira/browse/JENA-178?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13176157#comment-13176157
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Andy Seaborne commented on JENA-178:
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Using java.io.OutputStreamWriter and a java.io.BufferedWriter (8K buffer):
== On the 10th iteration (not checking for newlines)
XMLSAX out took: 275
XMLStax out took: 273
XML out took: 264
XML in took: 490
TSV out took: 124
TSV in took: 315
JSON out took: 580
JSON in took: 732
== On the 10th iteration (checking for newlines)
XMLSAX out took: 338
XMLStax out took: 275
XML out took: 439
XML in took: 462
TSV out took: 187
TSV in took: 324
JSON out took: 760
JSON in took: 773
Checked in (IndentedWriter left checking for in-string newlines for now).
revision 1224902
> SPARQL Results serialization is slow for some formats with large result sets
> ----------------------------------------------------------------------------
>
> Key: JENA-178
> URL: https://issues.apache.org/jira/browse/JENA-178
> Project: Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: ARQ 2.9.0
> Environment: Windows 7 Enterprise 64 bit
> Reporter: Rob Vesse
> Assignee: Damian Steer
> Fix For: ARQ 2.9.1
>
> Attachments: Jena178.java, Jena178.patch,
> TestArqSerializerPerformance.java, XMLOutputSAX.java, XMLOutputStAX.java
>
>
> The SPARQL XML and JSON Result formats are very slow when the result set is
> large. This is surprising to me since both formats are relatively simple and
> should lend themselves to fairly fast streaming serialization and parsing.
> The following are observed performance figures comparing SPARQL XML, SPARQL
> JSON and SPARQL TSV results format. This is the averaged time over 5 runs to
> retrieve the first 50,000 triples from the dataset with a simple SELECT *
> WHERE { ?s ?p ?o } LIMIT 50000 via a HTTP request to Fuseki and iterate over
> the results on the client.
> SPARQL XML = 15.25 seconds
> SPARQL JSON = 10.9 seconds
> SPARQL TSV = 0.54 seconds
> Now obviously TSV is way simpler to serialize and parse than XML/JSON but
> these serializers and parsers should not be 20-30 times slower IMO
> Also for comparison note that doing an equivalent CONSTRUCT { ?s ?p ?p }
> WHERE { ?s ?p ?o } LIMIT 50000 takes only about 2s and that is using RDF/XML
> serialization which I would have expected to be slower because RDF/XML is
> more complex to generate than either SPARQL XML/JSON results. I haven't
> dived into the code in detail to investigate why this is slow yet but do the
> Jena team have any thoughts on this?
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