====== Issues ======

====== fsck: dangling commit =====

List details about dangling commits ([[https://lukescott.co/2019/05/10/git-finding-lost-dangling-commits/|Git – Finding Lost/Dangling Commits]]:
<code bash>
git fsck --lost-found | grep "^dangling commit" | sed "s/^dangling commit //g" | xargs git show -s --oneline
</code>

Cleanup:
<code bash>
git reflog expire --expire=now --all
git gc --prune=now --aggressive
git repack -a -d
</code>

====== Reduce repo size ======


It is important to check if git configured with default settings.
Especially forcing of creation of multiple smaller packs significantly increases repository size.
I.e. changing one 1.2G pack into multiple 256MB packs let, increases size of packs to 4.3GB :(
<code bash>
git config --global -l
git config --system -l
</code>

Especially take attention for options like:
  *  deltaCacheSize = 10m
  *  packSizeLimit = 10m
  *  windowMemory = 10m


Command <code bash>git gc</code> and other cleaning commands requires whole repository to be read into memory. For big repos (like kernel.git) it requires to allocate over 8GB of RAM.
Compression of objects is also performed in RAM, then packs are written onto disc.
[[https://stackoverflow.com/questions/42175296/git-gc-uses-a-lot-of-memory-even-i-limited-it]]


To prevent touching existing packs and exhaust system memory paramter ''auto'' should be used. <code bash>git gc --auto</code>
Another possibility is to mark some packs as ''keep'' by creating .keep files. 

Remove unreachable objects:
<code bash>

git count-objects -v
git gc  --auto # this is enough to remove loose objects and repack repo
git count-objects -v

# more instruction
git repack -Ad # Remove dangling objects from packfiles
git prune # Remove dangling loose objects
git gc --aggressive --prune=now --force  || rm -f .git/objects/*/tmp_* && rm -f .git/objects/*/.tmp-*

git count-objects -v
</code>



====== error: pack-objects died of signal 9  ======

git was killed by host monitor process or oom due to memory usage.
Check syslog for OOM entries.

Solution:
<code bash>
[core]
    packedGitLimit = 32m
    packedGitWindowSize = 32m
    deltaCacheSize = 10m
</code>

Disable compression:
<code bash>
git config core.compression 0
git config core.loosecompression 0
git config pack.window 0
</code>


=== gitlab ===
git command running under user 'git' with gitlab installed looks for configuration in following places:
  * current git repo
  * /etc/gitconfig
  * /var/opt/gitlab/.config/git/config
  * **/var/opt/gitlab/.gitconfig**

This is a user config gile, and file is generated form
''/opt/gitlab/embedded/cookbooks/gitlab/templates/default/gitconfig.erb''

But if git binary from gitlab is used
<code bash>sudo -u git -H "/opt/gitlab/embedded/bin/git" config -l</code>

<code bash>
/opt/gitlab/embedded/bin/git --git-dir=/home/git-data/repositories/funny/linux.git config -l
/opt/gitlab/embedded/bin/git --git-dir=/home/git-data/repositories/funny/linux.git bundle create /tmp/linux.bundle --all
</code>

then, file  ''/opt/gitlab/embedded/etc/gitconfig'' is used.
To modify this file:

<file ruby gitlab.rb>
omnibus_gitconfig['system'] = {.
    "core"     => ["packedGitLimie = 32m", "packedGitWindowSze = 32m", "deltaCacheSize = 32m" ],
    "receive"  => ["fsckObjects = true"],
    "pack"     => ["deltaCacheSize = 32m", "packSizeLimit = 32m", "windowMemory = 32m", "threads = 2" ]
}
</file>

Test config:
<code>gitlab-ctl show-config</code>
Regenerate config:
<code>gitlab-ctl reconfigure</code>


<code bash>
sudo -u git bash
cd /var/opt/gitlab/git-data/repositories/{namespace}/{repository}.git
git gc --aggressive
</code>