On Saturday 29 August 2009, David Kalnischkies wrote: > > Would the following also work to use an *un*compressed packages file: > > Acquire::CompressionTypes::"" ""; > > A quick test suggest that this would work as a hack, but apt doesn't > like uncompressed files and will print many false-negative Ignore > messages. Debian doesn't provide an uncompressed file (main sid i368
Yes, I'm aware of that. It's a pity though as it could still make sense for local mirrors. I also don't see what the problem is. After all, APT itself saves the package file uncompressed in /var/lib/apt/lists (and IMHO should continue to do so). So why not support it when explicitly requested by the user. > would be ~28 MB) and if i am remember correctly apt doesn't even try to > acquire uncompressed files (expect for local archives with the method > file of course) per default. > > That's what I did, and it works great! I got a very notable speed > > improvement on my sparc box, and expect even better results for my > > s390 [...] > > I think it's worth mentioning, especially if you could also mention, > > as an example, that using gzip can improve speed on slower systems. > > Really? Never thought that there is a noticeable difference between the > two compression types if you add the increased downloadtime to gzip, > but i never tried/measured it... will be added to the news sidenote. Well, the trick is of course to have a local mirror :-) But maybe this can convince you. The uncompressed file is identical (23MB) for both timings (from my emulated s390 system) below: r...@mordor:~# time gunzip Packages.gz real 0m19.916s user 0m15.847s sys 0m4.041s r...@mordor:~# time bunzip2 Packages.bz2 real 1m37.161s user 1m28.808s sys 0m8.114s bzip2 really is a very horrible compression method for slower systems, and I'm *very* happy I can now avoid it. I think you'll agree that you'd either need a huge compression advantage or awfully slow network connection (even without a local mirror) to make up a 1:17 time difference for uncompression. I think you'll also see that fetching an uncompressed Packages file from a local mirror could also make sense in this case. I very much hope that we'll stay with gzip for package compression (unless the alternative is something that's comparably fast). Cheers, FJP -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
