git repack and dumb protocols

Hi there,

I've posted a git repository to the web that is an rsync copy of my development archive's .git directory, with update-server-info run on it. Now if I understand correctly, this contains a single file for every commit/file/whatever else I ever made, which is a paint over HTTP. I have then recently learned about the wonder that is git repack, which I would love to use on this repository, were it not for this comment in its manpage:

8< ---------------------------------------------------------------------- Especially useful when packing a repository that is used for private development and there is no need to worry about people fetching via dumb protocols from it. 8< ----------------------------------------------------------------------

It says this relating to the '-a' option, but it makes me wonder if I'll break copies of the repo that other people have pulled if I use 'repack'? What are the possible interactions and things to keep in mind between repack and dumb protocols?

In any case, I would like to suggest that the rather ominous-sounding text in the manpage be replaced with something more concrete, i.e. "If you repack an archive that has people fetching via dumb protocols from it, X, Y, and Z will happen."

Thanks, Andreas

(please cc--not subscribed)

The current text make some users feel uneasy, worrying whether '-a' could lead to corrupt repositories. Clarify that '-a' may lead to performance issues only for dumb protocols.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
---
Is that clear enough but concise?

Applies to maint.

 Documentation/git-repack.txt |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

The current text makes some users feel uneasy, worrying whether '-a' could lead to corrupt repositories. Clarify that '-a' may lead to performance issues only for dumb protocols.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
---
Is that clear enough but concise?

Applies to maint.

[Sorry for the resend, I managed to mistype the subject.]

 Documentation/git-repack.txt |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

Thanks, that's much better!

Andreas

On Donnerstag 04 Juni 2009, Michael J Gruber wrote:

On Thu, Jun 4, 2009 at 4:34 AM, Michael J Gruber<git@drmicha.warpmail.net> wrote:

Instead of adding this, why don't we just remove the part about dumb protocols? So just say that it's especially useful for private development. Then, if we really want to keep this performance note just add it after the paragraph in one of those "+" things (What are those called?)

Stephen Boyd venit, vidit, dixit 04.06.2009 21:46:

...because "repack -a" hurts *badly* on even midsized repos when dumb protocols are used. On the other hand, using it isn't that much of an improvement in terms of pack size, unless you repack manually very often and, thus, produce many small packs. So, "gc --auto" users should be fine in any case (dumb or not - the protocol, that is...) as long as they don't use "-a".

Michael

On Fri, Jun 5, 2009 at 1:16 AM, Michael J Gruber<git@drmicha.warpmail.net> wrote:

Maybe I spoke wrongly. I'm suggesting something like

       Especially useful when packing a repository that is used
       for private development.  Use with '-d'.  This will clean up
       the objects that `git prune` leaves behind, but
       `git fsck --full` shows as dangling.
+
Note: Users fetching over dumb protocols will have to fetch the
whole pack in order to get any contained object, no matter how
many other objects in that pack they already have locally.

I think this Note part probably needs some work though.

The current text makes some users feel uneasy, worrying whether '-a' could lead to corrupt repositories. Clarify that '-a' may lead to performance issues only for dumb protocols.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
---
Helped-by: Stephen Boyd <bebarino@gmail.com>

 Documentation/git-repack.txt |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

On Wed, Jun 3, 2009 at 7:50 PM, Andreas Klöckner wrote:

It won't break any copies, but it may cause excessive network use.

Dumb protocols can only fetch or not-fetch the entire pack. So if someone hasn't fetched since the last push, the next time they do a "git pull", they will retrieve the entire repository. Even if they only need a single small commit.

As you can imagine, people using dumb protocols over slow connections may become somewhat annoyed with the admin that often does a repack -a.

You do want to repack (usually without -a -- but see also ".keep") periodically, though. Working out a schedule depends on the activity level of the repository, and is left as an exercise for the reader.

Patches welcome.

Peter Harris