Comment 8 for bug 1709260

According to https://github.com/openstack/nova/blob/c0350da4a1607d7aa113caceaefb5d29303c7eed/nova/db/sqlalchemy/api_models.py#L53, there is no character set specified for the aggregate_hosts.host field (and there is no default in the oslo_db.sqlalchemy.models.ModelBase class) so the default character set will be latin1_swedish_ci.

It would be a fairly massive undertaking to "fix" this in all of Nova. We'd have to add default character set + collation clauses to all models and add a single DB schema migration that would change the character set and collation for all columns in question. This would require an offline data migration since it wouldn't be a happy instantaneous schema change. So, we'd have to add duplicate columns with the "correct" collation, migrate/copy all the old data into the new columns, then delete the old columns.