Re: Gnus is very slow in displaying headers.

[Kevin Greiner <kgreiner@xpediantsolutions.com>]

Daniel M. <xt@nm.ru> writes:

> Hello everybody,
>
> I noticed that even when I enter a group with a relatively small 
> amount of headers - in my case, 12000 for comp.lang.lisp, it takes 
> Gnus a very long time to thread/load them (headers are already in 
> the spool - they were downloaded previously by the Gnus) - 3 minutes 
> and 100% CPU for the duration of that period.
>
> Forte Agent, for example, has no problem with groups which
> contain hundreds of thousands of headers - it takes merely a couple 
> of seconds to load them, so it is not a lack of memory/CPU cycles.
>
> Am I doing something wrong, or is it a fundamental issue (elisp is too
> slow? something in the core of X/Emacs?) which renders Gnus unusable
> for anything more then a very small groups?

The problem is mostly likely due to your setting for
gnus-summary-line-format.  This is a string that describes the fields
displayed for each line of the summary buffer.  Internally, gnus
compiles this string into an elisp expression that inserts an article
into the buffer.  The approach is infinitely customizable but not very
optimizable.  You might look in the manual under 'Summary Buffer
Lines' to see if can identify a simplier string; one that meets your
requirements yet offers better performance.


> After searching the group for a similar questions, I saw an advice
> to set nntp-marks-is-evil variable to 't', which I have done, but 
> it made no noticable difference.

Right.  Nothing to do with your problem.

> I use Gnus 5.10.6 on Debian (precompiled package from unstable).
>
> BTW, listing of all active groups (zombie, killed groups - I am not 
> sure how I am supposed to call them. In effect, it is the list of all 
> groups carried by the server) also takes a lot of time - almost a full 
> minute, although there are only ~32000 groups and the file containing
> them resides on the HD. I even tried to sort that file, but it didn't 
> help :(.

I see the same thing, I just don't display the active list often enough to
try to optimize it.

Kevin