Large files are slow and unstable

[OverLordGoldDragon]

Demo. Observations:

• Scrolling is very slow
• Highlighting is very slow
• Adding / removing characters is very slow
• Adding / removing a character when entire file is highlighted leads to freeze/hang

Note: 18000 lines in the file

[ccordoba12]

Duplicate of #10992

[ccordoba12]

It'll be fixed in our next version.

[ccordoba12]

Several other perfomance improvements were already done and it'll be part of 4.0.1 too.

[jmoraispk]

@ccordoba12 I'm using Spyder 4.1.3 and I experience this exact issue with a file with just ~1000 lines. Less severe than the @OverLordGoldDragon 's demo, not sure if due to 18x fewer lines or due to some fixes, but it still is very noticeable.

[GitHunter0]

@ccordoba12 I'm using Spyder 4.1.3 and I experience this exact issue with a file with just ~1000 lines. Less severe than the @OverLordGoldDragon 's demo, not sure if due to 18x fewer lines or due to some fixes, but it still is very noticeable.

@ccordoba12 , I have the same problem, it makes Spyder, which is an awesome IDE, unusable. Shouldn't be the case to reopen this issue?

PS: JupyterLab is having the same issue, it lags and freezes when dealing with files that are not small.

[dalthviz]

Hi @fmgithub2017 and @jmoraispk we have #13020 open for some editor performance issues detected in Spyder 4.1.3 (we found that some options in the Editor are causing lag/performance issues, most notably Underline errors and warnings ). Maybe you can follow up there how we will be tackling the Editor performance issues :)

[GitHunter0]

@dalthviz , thanks man, closing the Outline Pane made a massive difference.

Just a quick unrelated doubt, the Ctrl+Shift+O shortcut just works to open the Outline Pane but not to close it (I have to do it via mouse clicks), is it right?

[dalthviz]

Glad you where able to work around the problem @fmgithub2017 👍

About the shortcuts, yep that shortcut only enables opening the Outline Pane, however there is global shortcut to close panes (Ctrl+Shift+F4) that will close the current focused pane

[GitHunter0]

Hey @dalthviz , thanks again.
It would be great if the same shortcut opens and closes its corresponding pane, but I will try your solution.
Cheers