[pacman-dev] Pacman database size study

[Allan McRae]

On 22/1/20 6:54 pm, Anatol Pomozov wrote:
> The first experiment is to parse db tarfile using the script and then
> write it back to a file:
>   uncompressed size is 17757184 that is equal to original sample
>   'zstd -19' compressed size is 4366994 that is 1.0084540990896713
> times better than original sample
>
> Tar *entries* content is identical to the original file. Uncompressed
> size is exactly the same. Compressed (zstd -19) size is 0.8% better.
> It comes from the fact that my script does not set entries user/group
> value and neither sets tar entries modification time. I am not sure if
> this information is actually used by pacman. Modification time
> contains a lot of entropy that compressor does not like.

tl;dr

"original"	4366994
no md5		4188019
no pgp		1160912
np md5+pgp	1021667


But do any of these numbers stand if you keep the tar file?

Also, I find downloading signature files causes a big pause in
processing the downloads.   Is that just a slow connection to the world
at my end?

Allan