Re: ostree.sizes metadata issues?

[Dan Nicholson <nicholson endlessm com>]

On Mon, Aug 24, 2020, 3:56 AM Alexander Larsson via ostree-list <ostree-list gnome org> wrote:

I notices that the endless ostree.sizes metadata support landed, and
I'm interested in using these to improve the flatpak download size
estimations.

However, I seem to remember that there was some kind of issue with
these the last time they were tried. Wasn't there a size limit for the
commit metadata or something that got overrun by large commits and made
this not work? Was something done to fix this?

It definitely works and I doubt any flatpaks will be larger than the OS we ship. I fixed several smaller issues when I was upstreaming it. The issue is that it makes the commit metadata really large for large commits. IIRC, our OS commit objects are like 4MB or something like that. So, it can make things a little show since ostree will always fetch the commit metadata when pulling. For smaller commits I don't think it would be much of an issue, but for runtimes you'd probably see it.

The other thing that's a little funky is that you need to do a metadata only pull to get it, which leaves the repo in a state where it thinks it has a partial commit and skips deltas as was found before. I think there are ways to handle it and flatpak already does something like this for a different reason I can't recall, but it's something I thought needed a better solution for in ostree.

I've always wanted to have flatpak use it, but I recall that you were opposed to it.