bug#35453: 26.1; Poor performance of vertical-motion in large org buffer

[Ihor Radchenko <yantar92@gmail.com>]

> There are no intervals in this story.  The way overlays are
> implemented, they don't use intervals (if by that you mean the
> facilities in intervals.c).  Someone was working on making overlays
> more efficient by changing the low-level implementation details, but
> that work is yet unfinished.

I see. Hope that overlays will be optimised eventually...

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Ihor Radchenko <yantar92@gmail.com>
>> Cc: 35453@debbugs.gnu.org
>> Date: Sun, 05 May 2019 09:05:46 +0800
>> 
>>   > Of course, if someone comes up with ideas how to speed up
>>   > vertical-motion without changing what Org does with overlays and/or
>>   > how overlays are implemented, such ideas will be most welcome.
>> 
>>   Rather dumb idea.
>>   Currently, vertical-motion just loops over all the intervals in the
>>   buffer. What if we optimise next-single-char-property-change and use it
>>   in vertical-motion? Say, the interval data structure can extended. In
>>   addition to the currently available pointers to next and previous
>>   intervals, each (or just 'invisible') property of the interval might
>>   also contain a pointer to next/previous interval with different property
>>   value. Then, by increasing the structure size a bit, we can
>>   significantly speed up the buffer motion commands.
>
> There are no intervals in this story.  The way overlays are
> implemented, they don't use intervals (if by that you mean the
> facilities in intervals.c).  Someone was working on making overlays
> more efficient by changing the low-level implementation details, but
> that work is yet unfinished.