find a severe bug

[zhaokun.ma]

I use apt 1.2.26 in ubuntu 16.04. "apt update" carries out normally. However, there are ppas in /var/lib/apt/lists. All other sources exist in partial directory. And There are nothing in pkgcache.bin except ppas and installed softwares

[TheFu]

Better help would be possible with copy/pasted errors. Please use text and code tags.

[zhaokun.ma]

Ign:18 http://mirrors.cn99.com/ubuntu xenial/multiverse arm64 Packages
Ign:26 http://mirrors.cn99.com/ubuntu xenial/universe arm64 Packages
Err:34 http://mirrors.cn99.com/ubuntu xenial-updates/main arm64 Packages
404 Not Found
Ign:44 http://mirrors.cn99.com/ubuntu xenial-updates/multiverse arm64 Packages
Ign:50 http://mirrors.cn99.com/ubuntu xenial-updates/universe arm64 Packages
Err:56 http://mirrors.cn99.com/ubuntu xenial-backports/main arm64 Packages
404 Not Found
Ign:63 http://mirrors.cn99.com/ubuntu xenial-backports/universe arm64 Packages
Err:71 http://mirrors.cn99.com/ubuntu xenial-security/main arm64 Packages
404 Not Found
Ign:81 http://mirrors.cn99.com/ubuntu xenial-security/multiverse arm64 Packages
Ign:87 http://mirrors.cn99.com/ubuntu xenial-security/universe arm64 Packages
Fetched 43.4 MB in 5s (8,239 kB/s)
AppStream cache update completed, but some metadata was ignored due to errors.
Reading package lists... Done
E: Failed to fetch http://mirrors.cn99.com/ubuntu/dists/xenial/main/binary-arm64/Packages 404 Not Found
E: Failed to fetch http://mirrors.cn99.com/ubuntu/dists/xenial-updates/main/binary-arm64/Packages 404 Not Found
E: Failed to fetch http://mirrors.cn99.com/ubuntu/dists/xenial-backports/main/binary-arm64/Packages 404 Not Found
E: Failed to fetch http://mirrors.cn99.com/ubuntu/dists/xenial-security/main/binary-arm64/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.

[wildmanne39]

Please use code tags - if you are using New Reply button - highlight text and use the # button in the text box header.

If using Quick Reply then
at the beginning and at the end.

[zhaokun.ma]

I think if the following sentence contains some information?

AppStream cache update completed, but some metadata was ignored due to errors.

because all the files exist in /var/lib/apt/lists/partial

[DuckHook]

As wildmanne39 has already requested, please post your output between
and tags for clarity. Or highlight the output and use the http://ubuntuforums.org/images/editor/code.gif button in the *Adv Reply* toolbar.

Also please use the standard text and colours for ease of readability.

[TheFu]

http://mirrors.163.com/ubuntu/dists/xenial-updates/main/ doesn't have any ARM repo that I see. Only see amd64 and x86 versions.

BTW, I used mirrors.cn99.com, but that was redirected to the above DNS name.

At any point previous, did the ARM repos work/exist? 16.04 should have until 2021 before they are removed.

[deadflowr]

Indeed the main repo never has any arm packages, those are all in the ports repository.
(Universe and multiverse, et al do have arm packages, but main never does.
Which is why it's erring out.

/var/lib/apt/lists/partial is for the info still in transit, which too makes sense as since the info is erring out the stored info will just still in there until things get fixed. (Or at least that's my take on it)
You can get the fix from post 4 from here: https://answers.launchpad.net/ubuntu/+source/apt/+question/661407

I think once you get the sources sussed out probably a good idea to wipeout the lists directory to allow it to start clean.

sudo rm -rf /var/lib/apt/lists/*
sudo apt update
sudo apt full-upgrade

[zhaokun.ma]

thanks for your answer, i will try:popcorn: