Git is not scalable with too many refs/*

Hello, Git. It is my 1st post here.

I have tried tagging each commit as "refs/tags/rXXXXXX" on git-svn repo locally. (over 100k refs/tags.) Indeed, it made something extremely slower, even with packed-refs and pack objects. I gave up, then, to push tags to upstream. (it must be terror) :p

I know it might be crazy in the git way, but it would bring me conveniences. (eg. git log --oneline --decorate shows me each svn revision) I would like to work for Git to live with many tags.

* Issues as far as I have investigated;

  - git show --decorate is always slow.
    in decorate.c, every commits are inspected.
  - git rev-tree --quiet --objects $upstream --not --all spends so much time,
    even if it is expected to return with 0.
    As you know, it is used in builtin/fetch.c.
  - git-upload-pack shows "all" refs to me if upstream has too many refs.

I would like to work as below if they were valuable.

  - Get rid of inspecting commits in packed-refs on decorate stuff.
  - Implement sort-by-hash packed-refs, (not sort-by-name)
  - Implement more effective pruning --not --all on revision.c.
  - Think about enhancement of protocol to transfer many refs more effectively.

I am happy to consider the issue, thank you.

...Takumi