On Wed, 29 Dec 2004, Garrett Rooney wrote:
> David Kramer wrote:
> >>That's not really true. When you make a copy of a large directory
> >>containing hundreds of files you're really not copying all the files.
> >>The number of files copied is not meaningful at all in determining how
> >>much space will be used in the repository, it's a constant amount for
> >>each copy, no matter how many files are involved.
> >
> > One of the things the book says you can do (in "Creating a complex
> > tag") is assemble a working copy that has mixed revisions (different
> > files at different revisions in the same working copy), and do an svn
> > copy of the working copy. If the repository doesn't have a record for
> > every single file in the new copy, how can it handle this scenario?
>
> Ok, you didn't say you were creating mixed revision copies. In that
> case it's a bit more complex. Let me try to explain.
>
> You need to realize that directories in the Subversion filesystem are
> basically collections of pointers to other entries in the filesystem
> (either files or other directories), and can refer to previous version
> of existing entities. So I can have something where /tags/0.1.0/foo
> really refers to revision 10 of /trunk/foo, even though at the time we
> created /tags/0.1.0 /trunk/foo was really at revision 15.
>
> To do this, there is some small additional cost as compared to a simple
> copy of /trunk to /tags/0.1.0. Normally, if I copy /trunk to /tags/blah
> then I need to create a new directory entry for /tags (which holds the
> new 'blah' entry in addition to whatever was there) and a new directory
> entry for / (which holds tags, trunk, and branches probably). If this
> was further down in the repository there would be other directories
> created as well, bubbling up from the copy all the way to the root.
>
> If you make a mixed-revision copy, all that same stuff gets copied, plus
> new directory entries need to be created for each subdirectory in the
> tree that contains mixed revisions. So if I want /tags/0.1.0/foo to be
> different from what exists in /trunk/foo when I make the copy I'll add
> one more directory entry, for /tags/0.1.0, which will have to record the
> fact that it's 'foo' entry points to /trunk/foo from that earlier
> revision.
>
> So the total cost is proportional to the number of directories that
> contain differences, relative to it's parent directory.
I understand about 92% of what you wrote, but if your last paragraph is
true, then I simply won't worry about it. Thanks for your advice.
----------------------------------------------------------------------------
DDDD David Kramer david_at_thekramers.net http://thekramers.net
DK KD
DKK D Live long and prosper. - Vulcan proverb
DK KD And eat well. - Jewish addendum to Vulcan proverb
DDDD Feast on your enemies! - Klingon interpertation of Jewish addendum
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Received on Thu Dec 30 14:33:50 2004