Access to on-premises data
- For live connections , the client 1) establishes a persistent connection to a Tableau Bridge service, which is the part of the client that resides on Tableau Online, using secure WebSockets (wss://). The client then waits for a response from Tableau Online before 2) initiating a live query to the on-premises data. The client 3) passes the query to the on-premises data, then 4) returns the on-premises data using 5) the same persistent connection.
- For extract connections that use Online refresh (formerly called Recommended) schedules , the client 1) establishes a persistent connection to a Tableau Bridge service, which is the part of the client that resides on Tableau Online, using secure WebSockets (wss://). The client then waits for a request from Tableau Online for new refresh schedules. When the client receives the requests, 2) the client contacts Tableau Online using a secure connection (https://) for the data source (.tds) files. 3/4) Then the client connects to the on-premises data using the embedded credentials in the request. The client 5) creates an extract of the data and then 6) republishes the extract to Tableau Online using the Tableau Bridge service. Steps 2-6 can be occurring in parallel to allow multiple refresh requests to happen.
- For extract connections that use Bridge (legacy) schedules , the client 1) contacts Tableau Online using a secure connection (https://) for new refresh schedules and data source (.tds) files. If 2) this information is available, at the scheduled time, 3/4) the client connects to the on-premises data using the stored credentials. The client 5) creates an extract of the data and then 6) republishes the extract to Tableau Online using a Tableau Bridge service. The Tableau Bridge service is a part of the client that resides on Tableau Online.