Bug?: The `rds_replication` role doesn't have the `replication` capability

Question

I noticed that the rds_replication role in my RDS Postgres DB doesn't actually seem to have the replication role set on them. Is this a bug?

```
=> SELECT rolname, rolreplication FROM pg_roles WHERE rolname = 'rds_replication';
     rolname     | rolreplication
-----------------+----------------
 rds_replication | f
(1 row)
```

Only the following roles have replication capabilities and none of them are assignable!

```
=> SELECT rolname, rolreplication FROM pg_roles WHERE rolreplication IS TRUE;
   rolname    | rolreplication
--------------+----------------
 rdsadmin     | t
 rdsrepladmin | t
(2 rows)
```

This has the impact that I'm unable to create a logical replication subscription since it errors with `ERROR:  could not connect to the publisher: FATAL:  must be superuser or replication role to start walsender` even after I assign the `rds_replication` role to my user.

Answer

I'm trying to setup replication from an external self-hosted DB. I'm trying to make the RDS DB to subscribe to that DB. 
The [docs seem](https://repost.aws/knowledge-center/rds-postgresql-use-logical-replication) to indicate this should be possible?

Answer

What are you trying to achieve? If you require a read replica you perform this via the RDS console.

There’s no need to change roles or create a replica via Postgres’s directly.

Bug?: The `rds_replication` role doesn't have the `replication` capability

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