Re: Re: Slow movement in large buffers

[Bastien <bzg@altern.org>]

Nick Dokos <nicholas.dokos@hp.com> writes:

> Given the evidence that Lawrence Mitchell provided however, it seems clear
> that most of the blame can be placed on overlays - no?

Yes, probably.

I've also experience slow motion in some big files of mine.

One factor was the use of the :ARCHIVE: tag.  I tried to remove this
tag, and things were fast again.  Another factor might be the use of
folded drawers and #+begin_src environments.

So I guess the problem boils down to 2 factors: the number of *nested
overlays*, and the number of lines in each.  How these factors interact
is hard to guess.

Instead of testing from org-issues.org (which is pretty messy), maybe 
we can have a testing/overlays.org file with a systematic structure?

#+begin_src org
* headline 1

** A subheading with 100 lines

lines ... lines (x 100)

* headline 2

** A subheading with 100 lines (x 100)
   :PROPERTIES:
   :LOCATION: Erewhon
   :END:

lines ... lines (x 100)

* headline 3

** A subheading with begin_src env and 100 lines (x 100)

  #+begin_src emacs-lisp
  (defun fixme ()
    "Some random defun"
    (message "This is not a message")
  #+begin_src

lines ... lines (x 100)

* headline 4

** subheading with archive tag and 100 lines :ARCHIVE: (x 100)

lines ... lines (x 100)
#+end_src

Matt, can you build and locally test such a file?  Then instrument
next-line when jumping from headline 1 to 2, to 3, to 4?

-- 
 Bastien