git-svn: Why not use git-fast-import?

git-svn: Why not use git-fast-import?

[Victor Leschuk]

Hello all, 

I've been playing with git-svn for some time already and as it seems to me there are two most important problems which make it hard to use in production for large repositories. Very low speed and large memory footprint of synchronization with SVN repos (I am talking about clone and fetch operations mostly). I was wondering why the git-fast-import is not used for these purposes? Are there any serious limitations which make it impossible?

I have found several alternative solutions which use git-fast-import but they all do only the initial import of a repo. I have looked through the documentation and didn't see why fast-import can't be used to sync an existing repo after the import. Am I missing something?

Thanks in advance for clarification.

Re: git-svn: Why not use git-fast-import?

[Jeff King]

On Tue, Sep 22, 2015 at 02:12:59AM -0700, Victor Leschuk wrote:

> I've been playing with git-svn for some time already and as it seems
> to me there are two most important problems which make it hard to use
> in production for large repositories. Very low speed and large memory
> footprint of synchronization with SVN repos (I am talking about clone
> and fetch operations mostly). I was wondering why the git-fast-import
> is not used for these purposes? Are there any serious limitations
> which make it impossible?

The main reason is that git-svn predates the invention of fast-import.
There was an attempt later to make a more "modern" svn interface:

  - it would provide a git-remote-helper interface (so you could use
    normal clone, fetch, and push with an "svn::" URL rather than a
    separate git-svn).

  - it would use fast-import for moving data into git

but it was never finished. I don't recall the specific problems offhand.
You can see the remnants in the vcs-svn directory of git, or you might
find discussions by searching the list archive.

-Peff