Measure / count objects in Git to see whether I am close to auto-packing

Question

I would like to measure / count objects in git to see whether I am close to auto-packing, I think it can be done trivially by counting files in .git/objects/..., but I am not sure.

Here is the story:

For a couple of days now, my git repo is auto-packing itself whenever I push to it. (The git repo lives on a USB memory stick, therefore the auto-packing is awfully slow and I have cancel it after 30 minutes or so)

it is the same problem as:

What does "Auto packing the repository for optimum performance" mean?

I'm having a problem with my git repo. For the last couple of days whenever I do a push to the server I get this message: "Auto packing the repository for optimum performance"

In that same thread I found the solution:

To disable for one project:

cd your_project_dir

git config gc.auto 0

To disable globally:

git config --global gc.auto 0

That solved my problem for that particular repo...

...but I have got many more git repo's on my memory stick and I would like to know a way to measure if any of my other git repos is close to auto-packing

I found:

Why does git run auto-packing on every push to our repo?

Git decides whether to auto gc based on two criteria:

Are there too many packs? (Literally, are there more than 50 files with .idx in .git/objects/pack?)

Are there too many loose objects? (Literally, are there more than 27 files in .git/objects/17?)

My question is almost answered, but I would simply like to have confirmation that I understand correctly: How can I measure / count loose objects to see if I am close to auto-packing ? -- is it (as suggested in the above answer) literally counting files in .git/objects/17 and compare to the hard limit of 27,

-- or maybe it is counting all files in .git/objects/01, .../02, .../03, etc... and comparing the average to a soft limit defined in git config global ?

-- even if it is trivial, is there a git command that counts objects in .git/objects/17 ? -- is there a git command that returns the hard limit of 27 ?

Answer 1

The answer at Why does git run auto-packing on every push to our repo? is still valid. As you can see in the source code of the latest release of git (2.10.2), this is the function need_to_gc that decides whether gc is run.

• Is the option gc.auto is set to 0 or negative?
• Are there too_many_packs: is the option gc.autopacklimit (default 50) positive and less than the number of packs (*.idx files in .git/objects/pack)?
• Are there too_many_loose_objects: is the option gc.auto (default 6700) positive, and is the number of loose objects in .git/objects/17 (it looks only in this directory; doesn't count all and take average or max or anything like that) greater than ({gc.auto} + 255)/256)?

So that's where the number 27 comes from: it's the floor of (6700 + 255)/256. You can increase it by increasing gc.auto. You can get the equivalent of this number 27 with the git command git config --get gc.auto but that only works if the option has been explicitly set.

Answer 2

I would like to measure / count objects in git to see whether I am close to auto-packing

Note that, as an indicator, Git 2.22 (Q2 2019) will help, since the "git pack-objects" command learned to report the number of objects it packed via the trace2 mechanism.

See commit 9ed8790 (11 Apr 2019) by Jonathan Tan (jhowtan).
^{(Merged by Junio C Hamano -- gitster -- in commit 3d67555, 08 May 2019)}

pack-objects: write objects packed to trace2

This is useful when investigating performance of pushes, and other times when no progress information is written (because the pack is written to stdout).

See Documentation/technical/api-trace2.txt for more on trace2, introduced in commit ee4512e in Feb.2019 for Git 2.22.