Does AWS provide support for RDS MySQL?
The FAQs at https://aws.amazon.com/rds/mysql/faqs/ state that AWS RDS provides MySQL Community Edition. If there is a defect found, does AWS provide the support for fixing the defect or do we have to wait until the defect is fixed by the community?
MySQL Community edition is a free version of MySQL with a limited function set. Small and medium projects won’t use advanced functions like database replication. MySQL community edition is not maintained by an open source community.
AWS does provide an on demand MySQL service based on MySQL community edition. It’s software however is Not maintained by AWS. Thus if there is a defunct, you have to wait until it is fixed by the vendor of MySQL. You benefit from maintained servers and instances by aws. You pay only for what you are using.
You can always create a EC2 instance in aws and maintain your own MySQL instance on your own responsibility. In this case you have to care about updates an security configuration.
I have experienced this first-hand in an AWS account with paid support. They helped identify the root cause and confirm the issue we were experiencing was a documented known issue with MySQL. No they would not develop a patch and submit a PR to the MySQL code-base, if that's what you mean by "support fixing the defect." Support in this case consists of documenting and helping you avoid or work around the issue.
For further reading: Known issues and limitations for MySQL on Amazon RDS