Note takes a lot of time to load

[Crowerade]

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• I have searched for similar issues (both open and closed) and cannot find a duplicate
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Describe the bug

Some long and heavy-coloured notes are really long to load when opening them (30 seconds to open). Might be related to #1474 .

To reproduce

1. Write a long note with a lot of different colours
2. Close it
3. Open it again

Expected behavior

Should load fast

Saber version

v0.25.8

Device

• Device: Galaxy Tab S6 Lite
• OS: One UI

Anything else?

No response

[Iey4iej3]

There seems nothing to do with colors. A duplicate of #1253

[Iey4iej3]

You could thumb up that issue so that it might appear in #1196 later.

[Crowerade]

Will do

[QubaB]

What is "long note". Can you specify it more precisely - show printscreen of one page - and say how much of similar pages has the note?

[Crowerade]

I would say for notes that are longer than about 15 - 20 pages. Pages are roughly all similar (same amount of hand-written text and drawings of different colours).
Here is a typical page

[QubaB]

Hmm, a lot of text on each page. You are using Fountain pen, it collects also "press" so more data for each point.

I am not creating such long notes so do not observing "long read time". Saber reads whole note (each page) to memory. It does not read first the page which should be displayed (as I understand the code). So it is probably the cause of problem.

I have no free time to try to improve code now. In fact I am not good Flutter programmer and improving this will probably need reading note on background while the first displayed page is read first.

[QubaB]

I briefly looked to code and it seems that almost all the time of loading note is spend in code:
json = BsonCodec.deserialize(bsonBinary);

It means that the note contents is loaded as binary file (very quickly). This routine transforms this binary file to json tree which is used as internal storage in Saber. I think that speed up of reading file can be done only storing json to saber note file, but note file will be much larger.

There is only way to speed up reading note file by changing the structure of note file. It is upon @adil192

[Iey4iej3]

I am not creating such long notes so do not observing "long read time". Saber reads whole note (each page) to memory. It does not read first the page which should be displayed (as I understand the code). So it is probably the cause of problem.

The effect is very obvious on slower devices, such as Onyx Boox. On S6 Lite, it is observable as long as your notes take, say, 10 pages, and in that case, the loading time is likely 3–5 seconds in my experience.

It means that the note contents is loaded as binary file (very quickly). This routine transforms this binary file to json tree which is used as internal storage in Saber. I think that speed up of reading file can be done only storing json to saber note file, but note file will be much larger.

The current file is already very large: I take notes for 2 years, and the notes are about 360 MB, while previously, I used Quill for 2 years and the notes are about 100 MB. I do not use fountain pens, but ballpoint pens.

Maybe the binary file could be slightly re-organized, so that different pages could be de-serialized independently.

[QubaB]

I created Draft pull request #1486 and also added comment to it in #1253 issue.

Someone can try if it will speed up loading of notes.