A fresh install of MySQL 8 on Linux yields the following default users for us:
debian-sys-maint
mysql.infoschema
mysql.session
mysql.sys
root
After creating our own users, with the correct privileges, we are thinking of deleting all the users, other than root (i.e. debian-sys-maint, mysql.infoschema, mysql.session and mysql.sys).
Q) Is it okay to delete the default users, other than root, or will there be any unexpected surprises if we do that?
>Solution :
Yes, there will be some unexpected surprises if you delete reserved accounts
You should not remove reserved accounts. All accounts has special purpose. All these reserved accounts are locked so that they cannot be used for client connections.
Check MySQL-8 docs on reserved accounts