How upgrading MariaDB Server failed because 50M warnings were ignored

This post is part of the series "please do not ignore warnings in MySQL/MariaDB".  The previous post of the series can be found here.

In this post, I will present why ignoring warnings made me lose time in upgrading MariaDB Server.  I think this war story is entertaining to read and it is also worth presenting to people claiming that ignoring warnings is no big deal.

Why I wrote "please do not ignore warnings" and "to always investigate/fix warnings" (in MySQL/MariaDB)

In a last post, I wrote the two following sentences:

• please do not ignore warnings
• always investigate/fix warnings

I realized that without context, this might be hard to understand.  In this post, I want to give more background about these two sentences.