Re: git gc ineffective

[Johannes Sixt <j6t@kdbg.org>]

Am 07.01.21 um 19:35 schrieb Michal Suchánek:
> Hello,
> 
> On Mon, Nov 09, 2020 at 12:17:57PM +0100, Andreas Schwab wrote:
>> On Nov 09 2020, Michal Suchánek wrote:
>>
>>> On Mon, Nov 09, 2020 at 11:17:38AM +0100, Michal Suchánek wrote:
>>>> On Mon, Nov 09, 2020 at 10:49:21AM +0100, Andreas Schwab wrote:
>>>>> On Nov 09 2020, Michal Suchánek wrote:
>>>>>
>>>>>> I noticed I am running out of disk space, and one repository taking up
>>>>>> about 38G. Did git gc --aggressive, and the used space *raised* to 42G,
>>>>>> and git would report it does gc after every commit.
>>>>>
>>>>> Do you have a lot of loose objects?
>>>> { for i in  .git/objects/?? ; do ls $i ; done ; } | wc -l
>>>> 53392
>>> And in the double-size repository it's doubled, too:
>>>  { for i in  .git/objects/?? ; do ls $i ; done ; } | wc -l
>>>  101167
>>
>> git count-objects also shows the size.
> $ git count-objects
> 59853 objects, 43249880 kilobytes
> $ du -hs .git
> 48G     .git
> $ git gc --aggressive
> Enumerating objects: 1825080, done.
> Counting objects: 100% (1825080/1825080), done.
> Delta compression using up to 4 threads
> Compressing objects: 100% (1803925/1803925), done.
> Writing objects: 100% (1825080/1825080), done.
> Total 1825080 (delta 1234005), reused 587969 (delta 0), pack-reused 0
> Removing duplicate objects: 100% (256/256), done.
> Checking connectivity: 2003814, done.
> Expanding reachable commits in commit graph: 337512, done.
> $ du -hs .git
> 172G    .git
> $ git count-objects
> 178734 objects, 175309572 kilobytes
> 
>> Does it help to prune them --exprire now?
> 
> $ git prune
> Checking connectivity: 1825478, done.
> $ du -hs .git
> 3.9G    .git
> $ git --version
> git version 2.26.2
> 
> So it is my wrong expectation that 'gc' comand removes garbage. It
> creates it en masse.
> 
> It just makes is in a way that the 'prune' command that really reoves
> garbage can now remove it.

It's an unfortunate default behavior of `git gc`. Set gc.pruneExpire to
'now' to countermand it, but watch out for the caveats.

See
https://stackoverflow.com/questions/55414916/how-to-avoid-that-git-gc-generates-garbage-loose-objects
for more details.

-- Hannes