I am creating a table in Redshift Serverless using Zero_ETL from DynamoDB and then creating a materialised view for use by a BI Dashboard, with the intention that the connection can only access the MV.

CREATE MATERIALIZED VIEW messages AUTO REFRESH YES AS
    SELECT  
        value.sender."S"::VARCHAR(10) AS sender, 
        value.source."S"::VARCHAR(10) AS source, 
        value.message."S"::VARCHAR(10) AS message, 
        timestamp 'epoch' + timestamp * interval '1 second' AS datetime 
    FROM "ddb_message"."public"."ddb-message";
    
grant select on table messages to bi_user;

According to .html "other users don't need to have the SELECT permission on the underlying base tables".

However when bi_user queries the MV they consistently get

SQL Error [XX000]: ERROR: Relation ddb-message does not exist in the database.

unless I also run

grant select on table "ddb_message"."public"."ddb-message" to bi_user;

Can anyone advise what is wrong here and how the necessity for granting select can be eliminated?

Thanks.