1. Create parameter group for character set and collation

RDS provides default parameter group. But it gives engine default value at character_set_server and collation_server, which is not proper for Korean and emoji. So I needed a custom one.

Create a parameter group

RDS - Parameter groups - Create parameter group

Name parameter group as you want.

I will use mariadb10.11 so I chose the group family.

Edit the parameter

Select the parameter group, then click Edit button.

Search keyword "server".

Change the two parameters as following.

character_set_server: utf8mb4

collation_server: utf8mb4_general_ci

It says that a collation is for ordering and calculation.

Q. Is it okay to change only character_set_server and collation_server? There are others with "character_set_" prefix.

A. Yes. And other character set parameters should not be set manually according to an official guide.

https://mariadb.com/kb/en/server-system-variables/#character_set_database

Q. I didn't set this variables in mariadb:10.11 docker but I could use Korean. Why was that?

A. The docker image of mariadb has set those parameters already because it's in Debian.

https://mariadb.com/kb/en/differences-in-mariadb-in-debian-and-ubuntu/