Performance of the man page database generation

[ludo@gnu.org (Ludovic Courtès)]

Hello,

Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:

> myglc2 <myglc2@gmail.com> writes:

[...]

>> It is taking more like 50 seconds on my 3.4 Ghz server for 33 packages.
>>
>>> I wonder why the odd package count mismatch (23 vs 22) ?
>>
>> That's my fault. I cut and pasted from two different runs. SORRY! ;-)
>>
>
> OK! No problem; thanks for clarifying it!
>
>>> I don't recall observing this while testing (maybe it only happens
>>> when using the -m option) ?
>>
>> No, I get the same effect w/ 'guix package -r foo.
>
> 50 seconds for 33 packages on such a powerful machine seems abnormal,
> unless you have a specific package(s) which would install an unusually
> large amount of manual pages (which would take more time to be indexed).
>
> Ludovic had a way to time the generation of the manual-database
> derivation; he was using something like [0]:
>
> time guix build --check /gnu/store/rkri628apz2a2i2jvav11ylv2736fvv3-manual-database.drv
>
> Notice that you need the derivation (.drv) of manual-database rather
> than the store item ending by manual-database. Unfortunately I'm not
> aware of how we can easily find the derivation of the corresponding
> manual-database store item used by the profile (as can be found by: guix
> gc -R $(realpath $HOME/.guix-profile) | grep manual-database).
>
> Maybe Ludovic can enlight us?

You can see those .drv names when building the profile.  So you just
need to copy/paste them and run “guix build --check” above.

If you have the profile but not its .drv, you can find out what the .drv
for that profile was but there’s no command-line interface for that (you
have to use ‘valid-derivers’ from (guix store).)

HTH,
Ludo’.