Oracle recently released Data Gateway as the successor to Remote Data Connectorin the Oracle Analytics Cloud 105.3 release earlier this year.
Remote Data Connector was originally part of the Oracle Analytics Cloud, OAC predecessor - Business Intelligence Cloud Service (BICS). It is used in order to allow for connectivity to an on-premise data source from an Oracle Analytics Cloud instance.
Why Data Gateway?
In a nutshell, the Remote Data Connector is a bit cumbersome and rather long winded in setting up with network, DMZ, firewall configuraton all required. It also requires either a Tomcat or WebLogic application server.
Most importantly, the communication between OAC and Remote Data Connector is started off by OAC. OAC requires access through DMZ, firewall etc to the Remote Data Connector. Data Gateway on the other hand controls and manages the communication between OAC and Data Gateway.
With Data Gateway, when a user's request requires data from an on-premise data source that has been configured with Data Gateway, an HTTPS request is made and held open by OAC. This is a technique called "long polling". The Data Gateway agent picks up the HTTPS request and passes the query to the on-premise database. The Data Gateway agent passes the query resultset back to OAC via a new HTTPS communication which is linked to the original HTTPS request.
In addition to the SSL certificates used in the HTTPS communication, the communication between OAC and the Data Gateway agent is further secured by the public/private key which encrypts all communication.
As multiple Data Gateway agents can be setup, the Remote Data Gateway can be used to maintain high availability by setting up 2 Data Gateway agents per OAC instance.