GNU bug report logs - #13675
24.2.93; Extremely slow redisplay when lines are very long

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Package: emacs;

Reported by: Eli Zaretskii <eliz <at> gnu.org>

Date: Sun, 10 Feb 2013 16:27:01 UTC

Severity: normal

Merged with 3219, 4123, 9589, 15555, 18530, 22143, 24523, 30457, 32523, 40007

Found in versions 23.1, 24.2, 24.2.93, 24.3, 24.5, 26.0.91, 27.0.50, 28.0.50

Fixed in version 29.1

Done: Lars Ingebrigtsen <larsi <at> gnus.org>

Bug is archived. No further changes may be made.

Full log

Message #26 received at 13675 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Mark Diekhans <markd <at> soe.ucsc.edu>
Cc: 13675 <at> debbugs.gnu.org
Subject: Re: bug#13675: Extremely slow redisplay when lines are very long
Date: Fri, 20 Oct 2017 09:44:30 +0300

> From: Mark Diekhans <markd <at> soe.ucsc.edu>
> Date: Thu, 19 Oct 2017 18:45:00 -0700
> 
> Is there anyone working on the long-line display speed issue?

Not that I know of.  I don't even have an idea for how to speed it up,
and I don't think anyone's come up with such ideas.

> It is especially bad with font lock mode.

What mode/kind of file needs font lock and has such long lines?

In general, if you must handle such files, my advice is to use M-x
find-file-literally for them, it might make Emacs just barely
bearable, if you are lucky.  But then you lose any font locking and
text encoding support, so this is only feasible for plain-ASCII files
that basically present some text.

> If the fix is really complex, it would be much better emacs
> refuse to display the file than force killing it.

Patches for presenting a warning for such files, like we do with very
large files, are welcome.
This bug report was last modified 2 years and 300 days ago.

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