Migrate PostgreSQL database to MySQL

Say that I want to migrate a PostgreSQL database on Heroku to MySQL on EC2 and I need to preserve the ID values in all the tables, what's the best way to accomplish that without开发者_JAVA技巧 using paid software?

It's quite simple.

I would have mySQL instance locally, heroku db:pull to get it from Heroku Postgres to your local development mySQL instance, back it up and then restore the backup to your EC2 MySQL instance