Re: filter-branch IO optimization

From: Jeff King <peff@peff.net>
Date: Oct 12, 2012, 17:20 UTC
Message-ID: <20121012172036.GB21409@sigill.intra.peff.net>
In-Reply-To: <9de87aac-7e15-48d9-832a-e9a030c5ed43@zcs>

On Fri, Oct 12, 2012 at 04:49:54PM +0200, Enrico Weigelt wrote:

Show 15 quoted lines

> > The usual advice is "use an index-filter instead".  It's *much*
> > faster
> > than a tree filter.  However:
> 
> I've tried the last example from git-filter-branch manpage, but failed.
> Seems like the GIT_INDEX_FILE env variable doesnt get honoured by
> git-update-index, no index.new file created, and so mv call fails.
> 
> My second try (as index-filter command) was:
> 
> git ls-files -s > ../_INDEX_TMP
> cat ../_INDEX_TMP |
>     sed "s-\t\"*-&addons/-" |
>     git update-index --index-info
> rm -f ../_INDEX_TMP

I didn't look closely at your individual problem, but that example has proven flaky before. There were some simpler formulations given in this thread:

  http://thread.gmane.org/gmane.comp.version-control.git/195492

In particular, Junio suggested:

  git filter-branch --index-filter '
    rm -f "$GIT_INDEX_FILE"
    git read-tree --prefix=newsubdir/ "$GIT_COMMIT"
  ' HEAD

-Peff