Re: Relative performance of text-properties search functions

[Thorsten Jolitz <tjolitz@gmail.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Thorsten Jolitz <tjolitz@gmail.com>
>> Date: Fri, 24 May 2013 19:26:39 +0200
>> 
>> > You were talking about outline or org-mode, so how is .emacs relevant?
>> 
>> Because my .emacs looks like this:
>> 
>> ,----------------------------------------
>> | ;; * init.el --- my Emacs Init File
>> | ;; ** Commentary
>> | ;; * Prerequisites
>> | ;; ** Start Message and Start Time
>> | ;; ** Setup Parts
>> | ;; ** Environment
>> | ;; ** Loading Emacs Lisp Libraries
>> | ;; ** Debugging
>> | ;; * [Screen Input Keys Cmd Enter Exit]
>> | ;; ** 1 (info "(emacs)Screen")
>> | ;; ** 2 (info "(emacs)User Input")
>> | ;; ** 3 (info "(emacs)Keys")
>> | ;; ** 4 (info "(emacs)Commands")
>> | ;; ** 5 (info "(emacs)Entering Emacs")
>> | ;; ** 6 (info "(emacs)Exiting")
>> | ;; * [Basic-Edit Minibuf M-x Help]
>> | [...]
>> `----------------------------------------
>> 
>> with outline-minor-mode and outshine.el activated. 
>
> Which is exactly the problem I was alluding to.  You may think that
> when you fold the buffer text like that that Emacs has no problems
> displaying that -- after all, those are just a few lines, right?  But
> in fact, the way Emacs display works, it must traverse the entire text
> of the portion of the buffer that corresponds to those header lines,
> skipping the folded text (which has the invisible text property), and
> displaying the rest.  Add to this replacing display properties, which
> you say will have to change all the time (whatever that means), and
> you might have annoyingly slow display operations, because replacing
> display properties are treated specially by the display engine, and so
> it constantly looks for them when it iterates over buffer text.

Although my init.el has some 7000 lines and lots of headlines, the usual
outline visibility and navigation commands work allright (although I
actually tend to use navi-mode for navigating in such big files), there
is no delay that makes using outline functionality uncomfortable. 

On the other hand, I already came to the conclusion that its and
illusion to have overlay cookies after all headlines that are updated
with every visibility change, that really takes the fun out of working
with such big buffers because of the frequent delays.

So its probably better to switch the cookies on when you need the info,
and switch them off otherwise.  

-- 
cheers,
Thorsten