Bug#881692: command-not-found: I re-wrote command-not-found

Shawn Landden slandden at gmail.com
Sun Nov 26 05:19:57 UTC 2017

On Mon, Nov 13, 2017 at 11:50 PM, Julian Andres Klode <jak at debian.org> wrote:
> (forwarding this to ubuntu-devel-discuss and Zygmunt)
> On Mon, Nov 13, 2017 at 10:33:39PM -0800, Shawn Landden wrote:
>> Package: command-not-found
>> Severity: wishlist
>> I re-wrote command-not-found to get rid of the python dependancy, and
>> to reduce the database size, as to reduce memory usage.
>> https://github.com/shawnl/command-not-found
>> I was preparing to upload it to mentors as command-not-found-ng
> I also rewrote it years ago, but using the same database format,
> just in C. It was a lot faster. I don't understand the memory usage
> bit - it should not matter how large the database is, it's memory
> mapped, and not read into memory, as such memory usage should be
> roughly constant.
> Questions/Comments for your approach:
> * Did you test your format on a slow HDD with caches dropped? It
>   must not be slower than the Python one (that one is way too slow
>   already) - I did, it seems to be faster (0.4 vs 0.68 seconds)
>   - I believe the database-based C rewrite was even much faster,
>   though.
I switched it to mmap() and am now getting 0.27-0.45 with caches
dropped, even after adding translations. It is 100% C and sh. (same
postinst and postrm)


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