Bug#703366: RFH: apt-file -- search for files within Debian packages (command-line interface)

[Stefan Fritsch <sf@sfritsch.de>]

On Monday 25 March 2013, Nick Black wrote:
> i ought point out here that raptorial-file does not have "update"
> or "purge" functionality. it seems to me that if the user has
> installed apt-file or some equivalent, they're interested in the
> contents of Contents files, and thus they ought be downloaded with
> apt updates. if they have not installed it, they can't use the
> data anyway, so don't download them. this can be done with apt
> hooks, no? and the first time it's installed it ought try to
> download contents. apt-file(1) as stands is perfectly reasonable
> at the update and purge task; we could gut it of "list"/"search"
> functionality, rename it apt-contents-get or something, and call
> it from the aforementioned hooks.
> 
> let me know if there's some reason why this is impossible (i do not
> yet pretend to grasp APT's semantics in their full detail).
> otherwise, let me know if you'd like me to proceed along this
> path, or who should do what, or whatever. i'd love to solve the
> longstanding annoyance of "apt-file update". i might be
> overlooking something obvious, though?

Well, the contents files are much larger than the package files and 
are usually used less frequently. So some users may prefer to download 
the contents files only when necessary. Apart from that, I don't see 
any problem. But that's not my decision anymore :-)


Other comments:

- Significant speedup could be attained by recompressing the local 
file with lzop instead of gzip. You write "processing time is roughly
characterized as at least twice inflation time" which is not what I 
remember from my experiments some years back. Decompression time was 
dominant (assuming a query that has only a few matches, which is the 
common case IMHO).

- Try benchmarks with a single core, too. It's nice if you can use 
more cores but you don't want to have too much regression on single 
core systems.

- apt-file regex search performance sucks because it doesn't use grep. 
Nowadays grep has -P, so grep could be used, too. Which regex type do 
you use?

- Are you limiting the used memory? Remember there may still be VMs 
with 256MB RAM and you shouldn't cause swapping on such systems.


Cheers,
Stefan