Posted On: Oct 15, 2020
Amazon Redshift Amazon Redshift now supports the ability to query across databases in a Redshift cluster. With cross-database queries, you can seamlessly query data from any database in the cluster, regardless of which database you are connected to. Cross-database queries can eliminate data copies and simplify your data organization to support multiple business groups on the same cluster. Support for cross-database queries is available on Amazon Redshift RA3 instance types.
Data is organized across multiple databases in a Redshift cluster to support multi-tenant configurations. However, you often need to query and join across these data sets by allowing read access. For example, different business groups and teams that own and manage data sets in their specific database in the same data warehouse need to collaborate with other groups. You might want to perform common ETL staging and processing while your raw data is spread across multiple databases. Organizing data in multiple Redshift databases is also a common scenario when migrating from traditional data warehouse systems. With cross-database queries, you can now access data from any of the databases on the Redshift cluster without having to connect to that specific database. You can also join data sets from multiple databases in a single query. You can access database objects such as tables, logical and materialized views with a simple three-part notation of <database>.<schema>.<object> and analyze the data using BI/Analytics tools. You can continue to setup granular access controls for users with standard Redshift SQL commands. This ensures that users only see relevant subsets of the data that they have permissions for.