systemd service is stopped and never restarted when mysql is being upgraded

[winternet-studio]

What steps will reproduce the problem?

Twice now it has happened that my server, which automatically installs patches, has upgraded mysql, and before it stops the mysql service it shuts down my service. Mysql upgrades and all is good - but my service is never restarted. How can that be? First I tried setting Restart=always instead of Restart=on-failure but that didn't help. Now I'm trying setting PartOf=mysql.service to see if they will help...

Or can I just leave out the mysql dependency altogether? Shouldn't it then always restart? Or will mysql disappearing just make the script hang/freeze and systemd think the service is running fine?!

What's expected?

My service should always run - which kind of is the whole purpose with systemd! :)

What do you get instead?

It dies when mysql is upgraded. Status says: "inactive (dead) since..."

Additional info

Q	A
Yii version	2.0.42.1
PHP version	7.4
Operating system	Debian 11 (Bullseye)

[samdark]

How does systemd determine if service is healthy?

[winternet-studio]

Must say I don't know how it determines that... I just followed the setup instructions from https://github.com/yiisoft/yii2-queue/blob/master/docs/guide/worker.md - but regardless of how it determines it, it realizes that it's not healthy since it says "inactive (dead)"... but it just doesn't restart it somehow...

[samdark]

I haven't observed such behavior personally and I wonder how to reproduce it...