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Posted to users@subversion.apache.org by Daniel Shahaf <da...@elego.de> on 2012/03/01 08:07:41 UTC
Re: Subversion for object code
Helmut Zeisel wrote on Wed, Feb 29, 2012 at 10:41:13 +0100:
> My interpretation of this is that "representation-sharing" works well
> enough for compiled C++ code, i.e. if I change 2% of source code and
> commit the changed objects and libs, then typically a comparable
> amount (+/- 2%) of the object code is additionally added to the
> repostory and the remaining +/- 98% can be reused from previously
> committed object code.
Representation sharing works only on complete files. (If two files are
not byte-for-byte identical, it never kicks in.) What you see would be
the xdelta binary-diff algorithm being efficient.
Re: Subversion for object code
Posted by Daniel Shahaf <da...@elego.de>.
Helmut Zeisel wrote on Fri, Mar 02, 2012 at 10:28:16 +0100:
>
> -------- Original-Nachricht --------
> > Datum: Thu, 1 Mar 2012 09:07:41 +0200
> > Von: Daniel Shahaf <da...@elego.de>
>
> > Representation sharing works only on complete files. (If two files are
> > not byte-for-byte identical, it never kicks in.) What you see would be
> > the xdelta binary-diff algorithm being efficient.
>
> OK.
>
> Does this mean that svn uses internally the same algorithm as xdelta (http://code.google.com/p/xdelta/)
>
I don't know offhand how close our implementation is to other
implementations or to research papers. There are some comments in
subversion/libsvn_delta/xdelta.c (lines 35 and 370) that suggest some
divergence from other sources.
CC'ing dev@ so people who know this code better can join the
conversation.
> This would mean that I could directly use
>
> xdelta3 -s SOURCE TARGET > OUT
>
> to estimate how big the differences between binary files are (without creating some svn test repository and measuring repostiory size)
>
> Helmut
>
> --
> NEU: FreePhone 3-fach-Flat mit kostenlosem Smartphone!
> Jetzt informieren: http://mobile.1und1.de/?ac=OM.PW.PW003K20328T7073a
Re: Subversion for object code
Posted by Daniel Shahaf <da...@elego.de>.
Helmut Zeisel wrote on Fri, Mar 02, 2012 at 10:28:16 +0100:
>
> -------- Original-Nachricht --------
> > Datum: Thu, 1 Mar 2012 09:07:41 +0200
> > Von: Daniel Shahaf <da...@elego.de>
>
> > Representation sharing works only on complete files. (If two files are
> > not byte-for-byte identical, it never kicks in.) What you see would be
> > the xdelta binary-diff algorithm being efficient.
>
> OK.
>
> Does this mean that svn uses internally the same algorithm as xdelta (http://code.google.com/p/xdelta/)
>
I don't know offhand how close our implementation is to other
implementations or to research papers. There are some comments in
subversion/libsvn_delta/xdelta.c (lines 35 and 370) that suggest some
divergence from other sources.
CC'ing dev@ so people who know this code better can join the
conversation.
> This would mean that I could directly use
>
> xdelta3 -s SOURCE TARGET > OUT
>
> to estimate how big the differences between binary files are (without creating some svn test repository and measuring repostiory size)
>
> Helmut
>
> --
> NEU: FreePhone 3-fach-Flat mit kostenlosem Smartphone!
> Jetzt informieren: http://mobile.1und1.de/?ac=OM.PW.PW003K20328T7073a
Re: Subversion for object code
Posted by Helmut Zeisel <HZ...@gmx.at>.
-------- Original-Nachricht --------
> Datum: Thu, 1 Mar 2012 09:07:41 +0200
> Von: Daniel Shahaf <da...@elego.de>
> Representation sharing works only on complete files. (If two files are
> not byte-for-byte identical, it never kicks in.) What you see would be
> the xdelta binary-diff algorithm being efficient.
OK.
Does this mean that svn uses internally the same algorithm as xdelta (http://code.google.com/p/xdelta/)
This would mean that I could directly use
xdelta3 -s SOURCE TARGET > OUT
to estimate how big the differences between binary files are (without creating some svn test repository and measuring repostiory size)
Helmut
--
NEU: FreePhone 3-fach-Flat mit kostenlosem Smartphone!
Jetzt informieren: http://mobile.1und1.de/?ac=OM.PW.PW003K20328T7073a