Register

Adv. Query

Q&A (4871)

Reviews (203)

Open problems (47)
Meta (439)

Site Statistics

205 submissions , 163 unreviewed
5,082 questions , 2,232 unanswered
5,353 answers , 22,789 comments
1,470 users with positive rep
820 active unimported users
More ...

"Preview" button slows down server response even after unticked?

1762 views

When half-way composing the post Some more questions on Haag's theorem, I ticked the "Preview" button to check whether the Latex were written correctly. After seeing everything was fine I un-ticked the "Preview" button, but the editor/server reponse was still very slow, in fact as slow as when "Live preview" button is ticked(just for the sake of comparison, I never ticked "live preview" when composing that post). Then I submitted the post, the server response becomes infinitely slow and I had to close the tab and compose my post all over again(I forgot to categorize my question so it should return me a notification, this may or may not add to the slowness....).

In fact I'm not sure if it's the fault of "Preview" or just a server glitch which happened to occur when I ticked and unticked the button.

asked May 3, 2015 in Bug by Jia Yiyang (2,640 points) [ revision history ]

That's odd... The preview button is only supposed to get a response from the server the moment it's ticked.

P.S. In case you encounter the issue again, rather than closing the tab and rewriting everything, you should be able to quickly ctrl+a ctrl+c the entire page content, and then select the relevant parts when you go about rewriting.

commented May 3, 2015 by dimension10 (1,985 points) [ revision history ]

I was unable to reproduce with the exact bug, but I found that there's an oscillating MathJaX output that says "Processing output: 100%" and "Typesetting output: 100%" intermittently. Do you observe this too?

And can you still reproduce the bug? If so, could you see if the bug is reproduced even when MathJaX is not involved?

commented May 3, 2015 by dimension10 (1,985 points) [ no revision ]

This is indeed very curious. For both types of preview, the server is not involved at all. The full preview checkbox calls a small javascript function, executed by your browser, which gets the actual content from the editor, puts it into a html <div> element, asks MathJax to render the math (which produces the text @dimension10 observes) and makes then this <div> visible. The live preview does something similar, but is triggered by the on-change event of the editor, so that its content is updated by every keystroke in the editor.

As I am revisiting actually the editor to implement a new feature, I will check this code in detail again. Please tell me should you observe this behavior again.

commented May 3, 2015 by polarkernel (0 points) [ no revision ]

@dimension10 @polarkernel, thanks for the feedback.

commented May 3, 2015 by Jia Yiyang (2,640 points) [ no revision ]

@polarkernel: I didn't observe slowdown, because the editing is ordinarily always fast for me even with preview, but I did observe what I interpreted as the thing processing TeX like crazy while editing an answer (from little announcements that said "Processing math" "Typesetting math" over and over, it is happening, even as I am editing this comments with a bit of gratuitious TeX thrown in: $\alpha + \omega$, even though I never clicked preview before it happened. You should definitely be able to reproduce it, just put an equation somewhere, and you can see the annoucements of typesetting/processing appear again and again every keystroke. For me, this is fast, but I assume it is unnecessary processing caused by preview always being enabled for some reason.

commented May 3, 2015 by Ron Maimon (7,730 points) [ revision history ]
reshown May 4, 2015 by Ron Maimon

@dimension10,

In case you encounter the issue again, rather than closing the tab and rewriting everything, you should be able to quickly ctrl+a ctrl+c the entire page content, and then select the relevant parts when you go about rewriting.

When I submit the post the page went completely blank and stuck, so it wouldn't work, I should've done so before submitting.

commented May 4, 2015 by Jia Yiyang (2,640 points) [ no revision ]

@JiaYiyang I see... that's quite bad. I guess the autosave feature polarkernel is developing might help with this.

commented May 4, 2015 by dimension10 (1,985 points) [ no revision ]

@RonMaimon I am able to reproduce what you describe. After some investigations I have found that MathJax gets triggered by the math-plugin of the editor, which I have not written myself. It has nothing to do with the preview features. I will try to change it. Maybe it could be configured to wait x milliseconds for another key before triggering the typesetting so that it gets only involved when you stop writing for a moment.

As I am actually writing a "save/autosave draft" feature for the editor, I will try to include a solution there.

commented May 4, 2015 by polarkernel (0 points) [ no revision ]

Your comment on this question:

To answer, leave an answer instead. Comments are usually for non-answers.
To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
To alert a user, please use the "@" command and remove spaces from the username, example, the user "John Doe" should be pinged as "@JohnDoe", while the user "Johndoe" should be pinged as "@Johndoe". The post author is always automatically pinged (unless you are the post author).
Please consult the FAQ for as to how to format your post.

Live preview (may slow down editor) Preview

Your name to display (optional):

Email me at this address if a comment is added after mine:

Privacy: Your email address will only be used for sending these notifications.

Anti-spam verification:

[captcha placeholder]

Please complete the anti-spam verification

Your answer

Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead.
To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
Please consult the FAQ for as to how to format your post.
This is the answer box; if you want to write a comment instead, please use the 'add comment' button.

Live preview (may slow down editor) Preview

Your name to display (optional):

Email me at this address if my answer is selected or commented on:

Privacy: Your email address will only be used for sending these notifications.

Anti-spam verification:

If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:
p$\hbar$ysicsOve$\varnothing$flow
Then drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds).

Please complete the anti-spam verification

user contributions licensed under cc by-sa 3.0 with attribution required

Your rights

...