[pacman-dev] [PATCH] pkgdelta: use highest compression ratio when creating deltas with xdelta3

[Jan Alexander Steffens]

On Thu, Mar 6, 2014 at 1:35 AM, Allan McRae <allan at archlinux.org> wrote:
> I'm assuming that is because that most of the time/memory is used
> applying the diff rather than decompressing it given it is quite small.
>
> I know memory usage and speed were issues when it was considered adding
> -9 to package compression.  My concern is this also applies to deltas.
> However, given the reconstruction of a delta is reasonably
> computationally intensive, I'm not sure this restriction applies here.
>
> Anyone else care to comment?

I've been running repo-add -d with XDELTA="-9 -S djw" to tease out
better ratios.

That said, with the current system delta + XZ is kinda suboptimal
since applying the delta requires recompression of the package and
XZ's compression times are so awful.