Re: "git notes show" is orders of magnitude slower than doing it manually with ls-tree and cat-file

[Mike Hommey <mh@glandium.org>]

On Wed, Nov 26, 2014 at 12:46:20PM +0100, Johan Herland wrote:
> (First of all, thanks to both for great investigation and analysis)
> 
> On Wed, Nov 26, 2014 at 5:46 AM, Jeff King <peff@peff.net> wrote:
> > On Wed, Nov 26, 2014 at 11:25:53AM +0900, Mike Hommey wrote:
> >
> >> Now, looking at the notes tree reflog, I see that at some point, some
> >> notes were added at the top-level of the tree, without being nested,
> >> which is strange.
> >
> > That's somewhat expected. The fanout is dynamic based on the number of
> > notes, so early on I think some notes may be found at the top of the tree.
> >
> >> And it looks like it's related to how I've been adding them, through
> >> git-fast-import. I was using notemodify commands, and was using the
> >> filemodify command to load the previous notes tree instead of using the
> >> from command because I don't care about keeping the notes history.
> 
> I'd very much like to see this fast-import stream (or a script
> generating it). I'm assuming that it roughly follows along these lines:
> 
>  - Start a new commit from a clean slate (no 'from')
> 
>  - Do a single filemodify to "load" the previous notes tree.
>    Exactly what does this filemodify command look like? I'm
>    guessing you're using the root tree object from the previous
>    notes tree as <dataref>, and an empty <path>, i.e.:
> 
>      M 040000 $previous_notes_tree_root_sha1 \n
> 
>  - Do a series of notemodify commands for the notes being added in
>    this commit.
> 
>  - End of commit.

That's exactly the scenario.

<snip>
> >   commit=$(echo "final notes tree" | git commit-tree refs/notes/foo^{tree})
> >   git update-ref refs/notes/foo $commit
> 
> I agree that this is probably the best workaround for now.

Indeed, that's about what I had in mind when I said I could easily work
around (except I use the ls command in fast-import), and what I
implemented.

Mike