Re: Why is git-clone --reference so slow?
- From
Junio C Hamano <junkio@cox.net>
- Date
- Feb 7, 2007, 10:03 UTC
- Message-ID
- <7vhcty8eui.fsf@assigned-by-dhcp.cox.net>
- In-Reply-To
- <1170676004.29759.767.camel@pmac.infradead.org>
David Woodhouse <dwmw2@infradead.org> writes:
> My DSL line sucks; I know this. But why is git-clone so bad at using it?
I did the same and it initially got 45MB pack (14.5k objects).
For my case, the reason was because the repository I used as the reference was pruned and packed its refs, and git-clone was not fully using the refs from the reference repository.
The following patch made it to be almost instantaneous. The resulting clone has 600kB pack (0.5k objects).
diff --git a/git-clone.sh b/git-clone.sh index 1710996..1bd54de 100755 --- a/git-clone.sh +++ b/git-clone.sh @@ -178,46 +178,32 @@ esac && export GIT_DIR && git-init ${template+"$template"} || usage if test -n "$reference" then + ref_git= if test -d "$reference" then if test -d "$reference/.git/objects" then - reference="$reference/.git" + ref_git="$reference/.git" + elif test -d "$reference/objects" + then + ref_git="$reference" fi - reference=$(cd "$reference" && pwd) - echo "$reference/objects" >"$GIT_DIR/objects/info/alternates" - (cd "$reference" && tar cf - refs) | - (cd "$GIT_DIR/refs" && - mkdir reference-tmp && - cd reference-tmp && - tar xf - && - find refs ! -type d -print | - while read ref - do - if test -h "$ref" - then - # Old-style symbolic link ref. Not likely - # to appear under refs/ but we might as well - # deal with them. - : - elif test -f "$ref" - then - point=$(cat "$ref") && - case "$point" in - 'ref: '*) ;; - *) continue ;; - esac - fi - # The above makes true ref to 'continue' and - # we will come here when we are looking at - # symbolic link ref or a textual symref (or - # garbage, like fifo). - # The true ref pointed at by it is enough to - # ensure that we do not fetch objects reachable - # from it. - rm -f "$ref" - done - ) + fi + if test -n "$ref_git" + then + ref_git=$(cd "$ref_git" && pwd) + echo "$ref_git/objects" >"$GIT_DIR/objects/info/alternates" + ( + GIT_DIR="$ref_git" git for-each-ref \ + --format='%(objectname) %(*objectname)' + ) | + while read a b + do + test -z "$a" || + git update-ref "refs/reference-tmp/$a" "$a" + test -z "$b" || + git update-ref "refs/reference-tmp/$b" "$b" + done else die "reference repository '$reference' is not a local directory." fi