All we need is an easy explanation of the problem, so here it is.
While upgrading mysql from 5.6 -> 5.7 -> 8.0.23 in step 5.7 -> 8.0.23 I got a warning:
The following objects use the utf8mb3 character set. It is recommended to convert them to use utf8mb4 instead, for improved Unicode support. More Information: https://dev.mysql.com/doc/refman/8.0/en/charset-unicode-utf8mb3.html common_schema - schema's default character set: utf8 mysql - schema's default character set: utf8 common_schema._global_qs_functions.function_arguments - column's default character set: utf8 common_schema._global_qs_variables.value_snapshot - column's default character set: utf8 common_schema._global_script_report_data.info - column's default character set: utf8 ...
So what means ‘mysql – schema’s default character set: utf8’? how can I change it to utf8mb4?
How to solve :
I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.
common_schema is a tool that someone added to your server? Sounds like it has not been updated to utf8mb4.
CHARACTER SET utf8 (aka utf8mb3) is old; utf8mb4 is new. The latter can handle Emoji and more of the Chinese character set, plus some less common languages.
If you don’t know anything about common_schema, ignore the warning.
In your tables, consider using utf8mb4. This is the default in 8.0; you would have to take deliberate action not to use it.
Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂