rt.
I have a secondary open source project on hand.
The PDO driver has been started before.
There will be a prompt in the log that there is a problem with the connection.
But only occasionally. It's not a big problem.

The template was changed some time ago.
The link is even more confusing. . . There are often errors, and it takes a long time to connect.
After changing mysql, mysqli or something, it is still the same.