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https://issues.apache.org/jira/browse/COMPRESS-285?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14052240#comment-14052240
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Wojciech Łozowicki commented on COMPRESS-285:
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I have very little knowledge concerning OSGi, so maybe I am wrong. Maybe there
is a way of checking if this call is made within OSGi context. If this check is
(or could be in some circumstances) also expensive, than it could be cached as
well (I think a class can loaded either in OSGi context or "standard" non-OSGi
context, so this cannot change). Then in case of execution in non-OSGi context
the availability of XZ compression could be cached.
> checking of availability of XZ compression is expensive - result should be
> reused
> ---------------------------------------------------------------------------------
>
> Key: COMPRESS-285
> URL: https://issues.apache.org/jira/browse/COMPRESS-285
> Project: Commons Compress
> Issue Type: Improvement
> Components: Compressors
> Affects Versions: 1.5, 1.6, 1.7, 1.8
> Environment: linux 64-bit, java 7, glassfish, solr, tika
> Reporter: Wojciech Łozowicki
> Priority: Minor
> Labels: performance
>
> I use solr with apache tika for indexing documents. Tika uses
> commons-compress to handle compressed files. Using sampler (jvisualvm) I have
> seen that quite a lot of time (5-7%) during my tests is spent in
> XZUtils.isXZCompressionAvailable because of unavailable XZ compression (I
> guess for each time classloaders spend some time looking for unavailable
> classes, then NoClassDefFoundError).
> I think the result of the first check should be stored and reused.
> Here is the stacktrace (just to show the way tika is using commons-compress):
> org.apache.commons.compress.compressors.xz.XZUtils.isXZCompressionAvailable(XZUtils.java:52)
> at
> org.apache.commons.compress.compressors.CompressorStreamFactory.createCompressorInputStream(CompressorStreamFactory.java:140)
> at
> org.apache.tika.parser.pkg.ZipContainerDetector.detectCompressorFormat(ZipContainerDetector.java:95)
> at
> org.apache.tika.parser.pkg.ZipContainerDetector.detect(ZipContainerDetector.java:81)
> at
> org.apache.tika.detect.CompositeDetector.detect(CompositeDetector.java:61)
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