Re: .deb format: let's use 0.939, zstd, drop bzip2

[Mike Hommey <mh@glandium.org>]

On Wed, May 08, 2019 at 09:01:27PM -0400, Michael Stone wrote:
> On Thu, May 09, 2019 at 07:37:55AM +0800, Paul Wise wrote:
> > On Thu, May 9, 2019 at 1:38 AM Adam Borowski wrote:
> > 
> > > Thus, even though we'd want to stick with xz for the official archive, speed
> > > gains from zstd are so massive that it's tempting to add support for it,
> > > at least for non-official uses, possibly also for common Build-Depends.
> > 
> > Could we use custom zstd dictionaries on a per-architecture basis to
> > further reduce the size of zstd packages, possibly allowing it to beat
> > xz?
> 
> In theory, sure. Have any test results? My gut tells me that wouldn't buy
> much but numbers matter more.

Another option is to use filters like xz does.
e.g.
https://git.tukaani.org/?p=xz.git;a=blob;f=src/liblzma/simple/x86.c;h=0b14807e900cdf4a85dc513c281892c2309bb454;hb=4ed339606156bd313ed99237485cb8ed0362d64f
https://git.tukaani.org/?p=xz.git;a=blob;f=src/liblzma/simple/arm.c;h=181d0e3b223220fa24cb5feb638b231357326905;hb=4ed339606156bd313ed99237485cb8ed0362d64f
https://git.tukaani.org/?p=xz.git;a=blob;f=src/liblzma/simple/armthumb.c;h=eab4862dd76dd03d4c0a0d8e4af7385866d9197d;hb=4ed339606156bd313ed99237485cb8ed0362d64f
etc.

Mike