Subject: Re: [PATCH 2/2] Run garbage collection with loose object pruning after svn dcommit

From: Andreas Ericsson <[email-masked]>
Date: Fri, 05 Oct 2007 10:04:02 +0200

Steven Grimm wrote:
> git-svn dcommit, by virtue of rewriting history to insert svn revision IDs,
> leaves old commits dangling.  Since dcommit is already unsafe to run
> concurrently with other git commands, no additional risk is introduced
> by making it prune those old objects as needed.
> 
> Signed-off-by: Steven Grimm <[email-masked]>
> ---
> 
> This is in response to a colleague who complained that, after I
> installed the latest git release, he was getting lots of "too many
> unreachable loose objects" errors from the new "git gc --auto" run.
> Those objects turned out to be dangling commits from a year's worth of
> git-svn usage, since every git-svn commit will abandon at least one
> existing commit in order to rewrite it with the svn version data.
> 
>  git-svn.perl |    6 ++++++
>  1 files changed, 6 insertions(+), 0 deletions(-)
> 
> diff --git a/git-svn.perl b/git-svn.perl
> index 777e436..be62ee1 100755
> --- a/git-svn.perl
> +++ b/git-svn.perl
> @@ -441,6 +441,12 @@ sub cmd_dcommit {
>  			}
>  			command_noisy(@finish, $gs->refname);
>  			$last_rev = $cmt_rev;
> +
> +			# rebase will have made the just-committed revisions
> +			# unreachable; over time that can build up lots of
> +			# loose objects in the repo. prune is unsafe to run
> +			# concurrently but so is dcommit.
> +			command_noisy(qw/gc --auto --prune/);
>  		}
>  	}
>  }

I'd be surprised if this would ever prune anything, as git doesn't throw out
objects reachable by reflog (or, I assume, any of the objects reachable from
objects reachable from reflog).

-- 
Andreas Ericsson                   [email-masked]
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231