man-db without cache update (no cron or systemd *.timer)

[Zbigniew Jędrzejewski-Szmek]

On Wed, Oct 15, 2014 at 05:12:07PM +0200, Peter Schiffer wrote:
> On 10/15/2014 04:47 PM, Chris Adams wrote:
> >Once upon a time, Jan Chaloupka <jchaloup at redhat.com> said:
> >>there has been a discussion about if we need cache for man-db for users
> >>which use man pages or update system only from time to time and thus
> >>don't need to update cache every day. man-db as it is now depends on
> >>systemd which brings another set of packages. The use case is "I just
> >>want to read man page. So I install man which on the other hand download
> >>another set of packages. I want to read man page and it downloads systemd.".
> >
> >On the majority of systems these days, is it really an issue to cache
> >man pages anymore?  I mean, back when a long man page (thinking about
> >some of the perl documentation for example) could take a while to
> >render, it mattered.  Now however, systems are much much faster, and we
> >expect GUI web browsers to render vastly more complicated content in a
> >fraction of a second.
> >
> >Maybe the time has come to just stop caching man pages at all, or at
> >least make that functionality optional (and non-default)?
> >
> 
> Hello,
> 
> I would add some noteworthy information:
> 
>  * the man-db cron/timer script is taking care of man DB containing
> only the man page title and short description i.e., the first NAME
> section of the man page. This DB is speeding up the searching in
> mentioned section with the man -k command. It is not used for
> displaying man pages or doing the full text search with man -K command
> and it is not required for normal usage of man command (man -k should
> also work without this DB).
> 
>  * Debian is updating this DB via deb hooks (or how it is called)
> during package installation/update and via daily cron script for man
> pages installed outside of package manager.
> 
>  * updating this DB is usually pretty quick, but creation can take some
> time..
> 
>  * man pages cache, pre-formatted man pages stored on disk in plain
> text, called cat pages in man-db context, is not used in Fedora.

I don't think that adding an additional subpackage to be manually
installed is worth the trouble. We should be making things simpler for
administrators, not require more manual involvement. From Peters'
description it seems it would be fine to simply ignore the timer and
not have the cache if systemd is not running for whatever reason. So
it would seem that ommitting systemd from the dependency list is the
answer. But omitting systemd from the dependency list is not possible,
because the dependency is necessary to order man-db after systemd in
case of a normal installation of both in one transaction. After things
calm down with F21, I'll return to the idea of splitting out
systemd-filesystem (name subject to change) to allow packages which
only need to enable a unit not to have a depenedency on full systemd
stack (see the thread "systemd dependencies" from August for recent
discussion).

Zbyszek