[PATCH] Script for automated historical Git tree grafting

[PATCH] Script for automated historical Git tree grafting

[Petr Baudis]

This script enables Git users to easily graft the historical Git tree
(Bitkeeper history import) to the current history.

Signed-off-by: Petr Baudis <pasky@suse.cz>

---
 git-gethistory.sh |   40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/scripts/git-gethistory.sh b/scripts/git-gethistory.sh
new file mode 100755
index 0000000..97b3e78
--- /dev/null
+++ b/scripts/git-gethistory.sh
@@ -0,0 +1,39 @@
+#!/bin/sh
+#
+# Graft the development history imported from BitKeeper to the current Git
+# history tree.
+#
+# Note that this will download about 260M.
+
+httpget="curl -O -C -"
+
+if [ -z "`which curl 2>/dev/null`" ]; then
+  httpget="wget -c"
+  if [ -z "`which wget 2>/dev/null`" ]; then
+    echo "Error: You need to have wget or curl installed so that I can fetch the history." >&2
+    exit 1
+  fi
+fi
+
+[ "$GIT_DIR" ] || GIT_DIR=.git
+if ! [ -d "$GIT_DIR" ]; then
+  echo "Error: You must run this from the project root (or set GIT_DIR to your .git directory)." >&2
+  exit 1
+fi
+cd "$GIT_DIR"
+
+echo "[git-gethistory] Downloading the history"
+mkdir -p objects/pack
+cd objects/pack
+$httpget http://www.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/objects/pack/pack-cc3517351ecce3ef7ba010559992bdfc10b7acd4.idx
+$httpget http://www.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/objects/pack/pack-cc3517351ecce3ef7ba010559992bdfc10b7acd4.pack
+
+echo "[git-gethistory] Setting up the grafts"
+cd ../..
+mkdir -p info
+# master
+echo 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 e7e173af42dbf37b1d946f9ee00219cb3b2bea6a >>info/grafts
+
+echo "[git-gethistory] Refreshing the dumb server info wrt. new packs"
+cd ..
+git-update-server-info


-- 
				Petr "Pasky" Baudis
Stuff: http://pasky.or.cz/
Right now I am having amnesia and deja-vu at the same time.  I think
I have forgotten this before.

Re: [PATCH] Script for automated historical Git tree grafting

[Andrew Morton]

Petr Baudis <pasky@suse.cz> wrote:
>
> This script enables Git users to easily graft the historical Git tree
>  (Bitkeeper history import) to the current history.

What impact will that have on the (already rather poor) performance of
git-whatchanged, gitk, etc?

Re: [PATCH] Script for automated historical Git tree grafting

[Petr Baudis]

Dear diary, on Fri, Apr 07, 2006 at 02:52:46AM CEST, I got a letter
where Andrew Morton <akpm@osdl.org> said that...
> Petr Baudis <pasky@suse.cz> wrote:
> >
> > This script enables Git users to easily graft the historical Git tree
> >  (Bitkeeper history import) to the current history.
> 
> What impact will that have on the (already rather poor) performance of
> git-whatchanged, gitk, etc?

Negative. ;-)

I didn't try gitk myself, but according to Nick Riviera it eats 1.6G...
Otherwise, assuming that you have at least git-1.2.5, git-whatchanged on
the whole tree should be roughly equally fast as it was before grafting,
but git-whatchanged on individual paths is _significantly_ slower.

That said, 1.3.0rc2 should already have Linus' optimization which should
fix or at least mitigate the performance hit on narrowed-down
git-whatchanged.

-- 
				Petr "Pasky" Baudis
Stuff: http://pasky.or.cz/
Right now I am having amnesia and deja-vu at the same time.  I think
I have forgotten this before.

Re: [PATCH] Script for automated historical Git tree grafting

[Nicholas Miell]

On Sat, 2006-04-08 at 05:09 +0200, Petr Baudis wrote:
> Dear diary, on Fri, Apr 07, 2006 at 02:52:46AM CEST, I got a letter
> where Andrew Morton <akpm@osdl.org> said that...
> > Petr Baudis <pasky@suse.cz> wrote:
> > >
> > > This script enables Git users to easily graft the historical Git tree
> > >  (Bitkeeper history import) to the current history.
> > 
> > What impact will that have on the (already rather poor) performance of
> > git-whatchanged, gitk, etc?
> 
> Negative. ;-)
> 
> I didn't try gitk myself, but according to Nick Riviera it eats 1.6G...
> Otherwise, assuming that you have at least git-1.2.5, git-whatchanged on
> the whole tree should be roughly equally fast as it was before grafting,
> but git-whatchanged on individual paths is _significantly_ slower.
> 
> That said, 1.3.0rc2 should already have Linus' optimization which should
> fix or at least mitigate the performance hit on narrowed-down
> git-whatchanged.

Actually, it ate more than 1.6G -- that was just the resident size, and
it likes to allocate more memory in between you closing the window and
it finally exiting (or, you killing it before it OOMs the box, whichever
comes first).

qgit has absolutely no problem with the grafted full history, though,
and those previously mentioned rev-list changes by Linus should fix
git-whatchanged.







Unfortunately, this does nothing to fix the disturbing lack of useless
Simpsons trivia knowledge in the git community. Keith Packard made the
same mistake last week.

-- 
Nicholas Miell <nmiell@comcast.net>