Lag when many downloaded items are loaded on Download page

[fynngodau]

Checklist

• I am able to reproduce the bug with the latest version given here: CLICK THIS LINK.
• I made sure that there are no existing issues - open or closed - which I could contribute my information to.
• I have read the FAQ and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one bug.
• I have read and understood the contribution guidelines.

Affected version

dev / 0.28..0

Steps to reproduce the bug

1. Download many videos (> 200)
2. Close app completely
3. Open app, navigate to Download screen

Expected behavior

• Database query is done on separate thread, UI does not lag
• Checking whether file exists is performed after the list is shown (items are removed after already being displayed)

Actual behavior

• Database query is done on main / UI thread
• Every file is checked individually, also on UI thread

Additional information

DownloadManager → loadFinishedMissions() is called upon init, which performs database queries and file system operations synchronously.

Note that > 200 checks whether files exist can also take multiple seconds.

Please also take a look at valuable comment from #9672 there is a attached logcat in it

[ShareASmile]

Bug is already reported in #9672, would you please make your observations noted in that issue (from a developer's prospective) as a comment there?

[Stypox]

@ShareASmile sorry we didn't find that issue, we tried searching for "lag" but couldn't find anything. Anyway, I would actually close the other issue in favour of this one as this one contains more information and we already started debugging the problem. (which btw seems hard to solve with the current downloader structure...)

[ShareASmile]

Okay, that is a good idea too. I would close that one to be able to track it easily here.

[sebma]

Related:#7879

[sebma]

@ShareASmile sorry we didn't find that issue, we tried searching for "lag" but couldn't find anything.

Try searching with the responding word instead :-)

[sebma]

@ShareASmile Should not the newer issues be duplicates of the #7879 instead ?