cd my_heroku_app

Make sure DB doesn't update on Heroku. This may be enough depending on your needs.

heroku maintenance:on

Dump from Heroku.

heroku pg:pull DATABASE_URL heroku_dump pg_dump heroku_dump -Fc > /tmp/db.dump # Fc for binary dump (otherwise the import will complain)

Restore to Dokku.

scp /tmp/db.dump my-dokku-server:/tmp ssh my-dokku-server "dokku psql:restore my-dokku-app < /tmp/db.dump"