Bug 294604

Summary: Composer is very slow when replying/inline-forwarding e-mails with a long body
Product: [Applications] kmail2 Reporter: itsef-admin
Component: composerAssignee: kdepim bugs <kdepim-bugs>
Status: RESOLVED UPSTREAM    
Severity: normal CC: montel
Priority: NOR    
Version: 4.8   
Target Milestone: ---   
Platform: Ubuntu   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description itsef-admin 2012-02-22 10:37:48 UTC 
Version:           4.8 (using KDE 4.8.0) 
OS:                Linux

Any time a mail with a long body (>1500lines) is being dealt with, Composer becomes very slow for both opening and navigating within the text. While doing so, Kontact thrashes the CPU up to 100%.

Reproducible: Always

Steps to Reproduce:
1) Select a mail with a long body (tried with > 1500lines)
2) Choose "Reply" or "Forward inline"

Actual Results:  
The composer window opens and remains inactive (grey) for several seconds - delays up to 10s have been observed. When open, navigating within the message body is also very slow - e.g. jumping from the end to the top (Ctrl-Home) can take 2-3s, again while thrashing the CPU. This makes dealing with long mails very cumbersome.

Expected Results:  
Composer should pop up quickly and be responsive within a short time. Navigating within the message text should be smooth and not dependent on text length.

- Set-up: Kubuntu 11.10 with either the original 4.7.4 packages or the Kubuntu-ppa 4.8.0 packages, IMAP account, NFS4 home directories, akonadi working with a central MySQL server.
- The bad performance was seen with both Nepomuk disabled and enabled.
- When using "Forward as attachment", Composer appears more or less instantly and is much more responsive - the slow down seems directly related to the length of the message body.
Comment 1 Laurent Montel 2012-02-25 11:12:53 UTC 
reply in html ?
Comment 2 itsef-admin 2012-02-28 07:57:45 UTC 
(In reply to comment #1)
> reply in html ?

No, plain text. Just tried again with an 1800-line body of copy-pasted plain text. Once Composer has started, enabling HTML format (Options -> Formatting (HTML) ) does not make a difference - jumping from top to bottom of the message is still very slow.
Comment 3 Laurent Montel 2012-03-29 16:57:43 UTC 
I confirm it but I can't change QTextEdit to QPlainTextEdit it's not support HTML.
Will wait that gsoc about use qwebkit to edit html email
Comment 4 itsef-admin 2012-09-06 15:32:57 UTC 
Is there anything going on with this? I just tried Kubuntu 12.04 -> Kontact 4.8.4 and this problem is very much present there... Thanks in advance!
Comment 5 Laurent Montel 2012-09-06 16:16:55 UTC 
We can't fix it for the moment. It's a problem with QTextEdit + long text.
Comment 6 itsef-admin 2012-09-06 16:37:19 UTC 
That's a pity. :-( Thanks for the quick response, though! Is there anything I can do like file a bug against QT or suchlike to support this?
Comment 7 Laurent Montel 2012-09-06 16:44:24 UTC 
Yes perhaps you can create bug report on qt directly.