Each RPI client can be configured to support one or more auxiliary databases, in addition to the main data warehouse. Data stored within auxiliary databases can be used for targeting and segmentation purposes. Note that appropriate joins between the data warehouse and auxiliary databases must exist – it is not possible to use an auxiliary database table as an interaction resolution table, nor is it possible to write offer history data to an auxiliary database.
All of the supported database management systems suitable for data warehouse use can be used to host an auxiliary database. In addition, the Amazon Athena, Amazon Redshift Spectrum, Apache Hive, Apache Spark, Apache Drill, Cassandra, Google Big Query, Google BigTable, Google Spanner, MarkLogic, Microsoft Azure Cosmos DB, Salesforce.com, MapR DB platforms can be used to host auxiliary databases only. The MongoDB, CosmosDB, Couchbase, Amazon Document DB and Google Datastore NoSQL database platforms can also be used to host auxiliary databases.