Re: Slow movement in large buffers

[Carsten Dominik <carsten.dominik@gmail.com>]

On 15.3.2011, at 18:14, Scott Randby wrote:

> On 03/15/2011 12:11 PM, Chris Randle wrote:
>> Hi Matt
>> 
>> On 2011-03-15 03:25, Matt Lundin wrote:
>>> I've been navigating the org-issues file (14000+ lines) and have
>>> found movement within the file to be fairly slow. Sometimes Emacs
>>> will lock up for several seconds.
>> <snip>
>>> Do others have the same experience? If so, does anyone have any tips
>>> on how to diagnose this further?
>> 
>> I keep all my info in one big Org-mode file which is currently just shy
>> of 115,000 lines. There's the occasional "stutter" of a fraction of a
>> second when I move across closed nodes containing large chunks, but it's
>> still perfectly acceptable (to me, anyway!).
>> 
>> My PC is an Intel dual-core 2.66GHz with 4GB RAM, so nothing
>> earth-shattering.
>> 
> 
> I have a netbook running an Intel dual-core 1.66GHz and 2GB RAM. I
> opened up org-issues.org and navigated through it without difficulty.
> There was a delay for about a second when I unfolded the "Development
> Tasks" headline, but there were no delays after that. Vertical movement
> is instantaneous.


One reason why the motion in a folded buffer is slow:
calling next line on the heading of a folded tree must
move down potentially thousands of buffer lines.  In each buffer
line it checks if the text is still invisible and then moves one.
So this kind of buffer motion is not optimized for outline
buffers.  Still, what Matt and others report is unacceptable,
and there must be a solution.  I have very slight delays
in org-issues.org, but nothing like 5 seconds.   Fractions
of a second, at most.

- Carsten

> 
> Scott Randby
>