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Deltification and Jars

From: Travis P <svn_at_castle.fastmail.fm>
Date: 2004-04-01 03:18:20 CEST

I'm considering version-controlling finished Java jars that are
promoted into production. A jar is essentially a zip file. I'm
scratching my head wondering if I should build double-big jars with the
no-compression option so that the Subversion repository will grow
linearly with the size of the changes rather than rather having to save
a big difference because of changes that cause a shift in compression
making everything else appear different. I'm likely to make numerous
promotions with small changes.

I believe that compressed files would tend to require deltas that
comprise the whole content of the file after the first change is
encountered. On the other hand, jars compress per-file and the files
(class files and support files of text and graphics) tend to be quite
small (currently my largest is < 30K). So the changes are likely to
remain small as most class files and support files are small. This is
different than if everything were, say, gzipped in a .tar.gz file.

I'm curious if anyone has already waded into these waters to consider
the relative merits/demerits of using Subversion on zip/jar files and
whether turning off compression is useful or not? I imagine that this
issue will come up for several people.

My current suspicion is that I can just use compression and not worry
about it. Using compression is my preference since the jars are
distributed to users over networks via distributed filesystems.


p.s. 1:
   Thus URL:
   mentioned in a comment in
   is no longer valid.

p.s. 2:
   mentions a paper. Looks like the paper was updated and re-published
   "Delta algorithms: an empirical analysis"
   ACM Transactions on Software Engineering and Methodology (TOSEM)
   Volume 7 ,  Issue 2  (April 1998) Pages: 192 - 214

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Received on Thu Apr 1 03:16:49 2004

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