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https://issues.apache.org/jira/browse/PDFBOX-441?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Frank Nestel updated PDFBOX-441:
--------------------------------
Attachment: COSName.java
Remarks:
- The cleanResources thing is a hack, in a major environment, since it is not
clear who should call it when.
- We had used a ConcurrentHashMap here at some other time. This caused major
speed improvement then (older PDFbox anyway). However we realized we would not
stand the leak.
- What would really be grat would be a beast like
http://www.stacksmash.com/jsr166y/ This would allow a ConcurrentHashMap using
weak references, one could simply put all the statics in, since they are
strongly references they will never get cleared.
- In between attached find the beast we are currently relying upon, which is
weakreferences done right (the PDFbox 1.1 version is still leaky, since each
COSname keeps a strong reference to its key) and with (semi-)fast read/write
locking.
- Note that we removed the hashCode field member is a deoptimization, since
common Java implementations have an hashCode field in their String class anyway
(this wasn't true in earlier times, so for old environments this field might
still be an optimization)
> remove CosName nameMap cache
> ----------------------------
>
> Key: PDFBOX-441
> URL: https://issues.apache.org/jira/browse/PDFBOX-441
> Project: PDFBox
> Issue Type: Improvement
> Affects Versions: 0.7.3
> Reporter: Sean Bridges
> Priority: Minor
> Fix For: 1.2.0
>
> Attachments: COSName.java
>
>
> The CosName class keeps a cache of all instances created in a static
> synchronized map. I am guessing this is for performance reasons to avoid
> creating objects, but in our system it is causing performance problems. We
> are running 7 threads extracting text from pdf's, and we can see a large
> number of conflicts reading from nameMap.
> The CosName map is also a potential memory leak, which forces users to
> periodically clear it, as noted in PDFBOX-351
> Can nameMap be removed altogether?
> At the least, if PDSimpleFont replaced,
> COSName.getPDFName( "FontDescriptor" )
> with
> COSName.FONT_DESC
> It would reduce contention.
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