Hi Andrea,
While a speed improvement in parsing of large files would be much
appreciated (especially by the TIKA users), there are several problems
with your change:
- don't do changes that need JDK7 or higher even if they are cool. We
use JDK6 currently.
- regressions:
Error converting file PDFBOX-2250-110264-xref-zeronumber.pdf
java.io.IOException: XREF for 3:0 points to wrong object: 1:0
at
org.apache.pdfbox.pdfparser.COSParser.parseObjectDynamically(COSParser.java:696)
at
org.apache.pdfbox.pdfparser.COSParser.parseObjectDynamically(COSParser.java:639)
at
org.apache.pdfbox.pdfparser.COSParser.parseDictObjects(COSParser.java:600)
at
org.apache.pdfbox.pdfparser.PDFParser.initialParse(PDFParser.java:346)
at org.apache.pdfbox.pdfparser.PDFParser.parse(PDFParser.java:373)
at org.apache.pdfbox.pdmodel.PDDocument.load(PDDocument.java:811)
at org.apache.pdfbox.pdmodel.PDDocument.load(PDDocument.java:757)
at
org.apache.pdfbox.util.TestPDFToImage.doTestFile(TestPDFToImage.java:201)
at
org.apache.pdfbox.util.TestPDFToImage.testRenderImage(TestPDFToImage.java:343)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at junit.framework.TestCase.runTest(TestCase.java:176)
at junit.framework.TestCase.runBare(TestCase.java:141)
at junit.framework.TestResult$1.protect(TestResult.java:122)
at junit.framework.TestResult.runProtected(TestResult.java:142)
at junit.framework.TestResult.run(TestResult.java:125)
at junit.framework.TestCase.run(TestCase.java:129)
at junit.framework.TestSuite.runTest(TestSuite.java:255)
at junit.framework.TestSuite.run(TestSuite.java:250)
at junit.textui.TestRunner.doRun(TestRunner.java:116)
at junit.textui.TestRunner.start(TestRunner.java:183)
at junit.textui.TestRunner.main(TestRunner.java:137)
at org.apache.pdfbox.util.TestPDFToImage.main(TestPDFToImage.java:393)
Error converting file PDFBOX-2599.pdf
java.io.IOException: XREF for 2:0 points to wrong object: 1:0
at
org.apache.pdfbox.pdfparser.COSParser.parseObjectDynamically(COSParser.java:696)
at
org.apache.pdfbox.pdfparser.COSParser.parseObjectDynamically(COSParser.java:639)
at
org.apache.pdfbox.pdfparser.COSParser.parseDictObjects(COSParser.java:600)
at
org.apache.pdfbox.pdfparser.PDFParser.initialParse(PDFParser.java:346)
at org.apache.pdfbox.pdfparser.PDFParser.parse(PDFParser.java:373)
at org.apache.pdfbox.pdmodel.PDDocument.load(PDDocument.java:811)
at org.apache.pdfbox.pdmodel.PDDocument.load(PDDocument.java:757)
at
org.apache.pdfbox.util.TestPDFToImage.doTestFile(TestPDFToImage.java:201)
at
org.apache.pdfbox.util.TestPDFToImage.testRenderImage(TestPDFToImage.java:343)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at junit.framework.TestCase.runTest(TestCase.java:176)
at junit.framework.TestCase.runBare(TestCase.java:141)
at junit.framework.TestResult$1.protect(TestResult.java:122)
at junit.framework.TestResult.runProtected(TestResult.java:142)
at junit.framework.TestResult.run(TestResult.java:125)
at junit.framework.TestCase.run(TestCase.java:129)
at junit.framework.TestSuite.runTest(TestSuite.java:255)
at junit.framework.TestSuite.run(TestSuite.java:250)
at junit.textui.TestRunner.doRun(TestRunner.java:116)
at junit.textui.TestRunner.start(TestRunner.java:183)
at junit.textui.TestRunner.main(TestRunner.java:137)
at org.apache.pdfbox.util.TestPDFToImage.main(TestPDFToImage.java:393)
- why change only one of the members of that cosobjectkey class to int?
According to the spec, both are integers. Maybe there's a good reason,
but I'd like to know.
- even if you get rid of the regressions, a remaining problem is that
- Andreas L. is currently working on some parser stuff in PDFBOX-2527
- your change is too big to evaluate (I'm speaking only for myself
there). It would be better to first submit only small refactorings in
PDFBOX-2576, and then the optimization you mention (or the other way
around). The parser is indeed a tricky part of the code (And SonarQube
and Software Diagnostics have also flagged it as too complex). I did
some refactorings a few weeks ago there (splitting methods), but stopped
because I couldn't come up with names for the new methods. I just didn't
understand what they were doing.
Tilman
Am 27.02.2015 um 16:34 schrieb Andrea Vacondio:
Hi,
few days ago I was profiling PDFBox when loading medium/large size
documents and I think I found something.
If you try loading the document
http://www.adobe.com/devnet/acrobat/pdfs/pdf_reference_1-7.pdf you'll see
it takes quite some time and that's mostly spent in the
XrefTrailerResolver.getContainedObjectNumbers. The issue is that every time
an object contained in an unparsed object stream is found, the
XrefTrailerResolver performs a full scan of the xref entries found in the
document, in this case hundreds of thousands. If the object streams are
many (like in the given doc), it performs many full scans resulting in poor
performance.
I'm trying to get familiar with the PDFBox code and I decided to try and
fix this herehttps://github.com/torakiki/sambox/tree/xref
As you can see I refactored a bit extracting some classes and covered the
expect behaviour with unit tests. I tested it with few random docs, loading
and saving them back and the output is exactly the same with or without my
changes. The pdf_reference_1-7.pdf doc loads in half of the time, same as
this
http://wwwimages.adobe.com/content/dam/Adobe/en/devnet/pdf/pdfs/PDF32000_2008.pdf
it takes half the time. Other kind of docs loads in a comparable amount of
time and even profiling memory usage it seems comparable if not a little
less.
Maybe someone wants to take a look?
I understand my changes look a bit invasive and the issue could probably be
fixed differently, on the other hand the couple BaseParser+COSParser looks
like a big intimidating monster to a newcomer like me and it's quite
difficult to follow the expected behaviour so I thought this might be a
chance to start breaking them down in smaller, distilled classes...
something a little more manageable and testable... anyway, grab what you
like, leave what you don't :)
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