Lag when switching between block and classic editor on long posts

[hypest]

Originally reported here.

Switching to Classic editor makes the app hang (ANR) for a bit until everything is loaded and then it works alright (scrolling fast and all) but you do have to wait a fair 10-15 seconds for the thing to be responsive. It hangs, goes black for a second, appears (but you can't scroll or anything) and have to wait.

Here's the Post used (it's basically the demo Gutenberg content pasted several times) https://selfhostedmario.mystagingwebsite.com/2019/03/welcome-to-the-gutenberg-editor/

For the record, using the content mentioned here wordpress-mobile/gutenberg-mobile#672 on Aztec makes it take a long time to load and be responsive, same as with the aforementioned Gutenberg post when switching and opening it on the Classic Editor.

On Aztec, switching to HTML mode and trying to add / modify text there is super slow.

[designsimply]

Adding some links to sample data which can be used for testing large posts:

1. Gutenberg Demo Post
2. Lipsum generator (enter 10000, select "words", click Generate Lorem Ipsum)
3. Performance: Improve the initial loading time and the feeling fo smoothness while typing in blocks. WordPress/gutenberg#11782 (comment)
4. Extensive articles with over 1700 words and various blocks make Gutenberg very slow. WordPress/gutenberg#10418 (comment)

[cassgenerator]

Looking into this issue in WordPress-Android I have found that the majority of the time taken when switching to the "classic editor" is caused by Aztec. I have logged an extensive issue in that repository highlighting some areas to look into for performance improvements.

I would advise closing this issue as it doesn't look like this is primarily related to Gutenberg-mobile.

[hypest]

👋 @drspaceboo , thanks for diving into this one! Reason this ticket was originally created here was for better tracking within the gutenberg-mobile GitHub project and because it refers to the whole flow of switching editors on the fly. Switching editors on the fly encompasses another slow process (the saving of data) and perhaps more reasons so, I'd recommend we keep this ticket open anyway. When we fix the Aztec slowness side we can update this ticket too. How's that sound?

[cassgenerator]

Makes sense to me 💯

[KokkieH]

We have a user report of this issue in https://en.forums.wordpress.com/topic/wordpress-android-app-3/

My WordPress app’s version is 12.9 and my android version is 5.0.2 and my phone is HTC Desire 820s dual sim.

With large text (this one i’m working on is approximately 11 pages long) while switching between classic and block editor the app seems to struggle with it for maybe 10-15 seconds.
And when it finally opened the classic editor i tried to continue editing yet unfortunately it kept lagging so much so i would type and the words would appear on screen maybe 6-10 seconds later and sometimes longer even though it didn’t lag at all when i switched back to the block editor and it worked smoothly.

[hypest]

"Switch to classic" has been removed for some time now so, closing this ticket. Happy to reopen if it still holds for some flow. Thank you all!