Understanding cached previews and metadata
When mobile users interact with content on Tableau Server or Tableau Online, the server processes the underlying business data, and the Tableau Mobile app renders it for display. To display content more quickly, Tableau Mobile caches the following content on a user's device:
Previews of favourite workbooks and views that users can quickly access online or offline.
Metadata about favourite workbooks and views, such as name and the time of last synchronisation with the server.
This content is securely stored using best practices for each mobile platform. On iOS, previews and metadata are encrypted when a device is locked with a passcode, and cached files are excluded from OS backup processes. On Android, we recommend requiring passcodes and device encryption, which sometimes aren't enabled by default; to automatically apply this setup across all your Android devices, use an MDM or MAM solution.
For further protection, locally stored data is completely deleted whenever:
A user signs out of the server or uninstalls the Tableau Mobile app.
You remove a user account from Tableau Server or Tableau Online, and the user tries to sign in with Tableau Mobile.
For maximum control, we recommend managing devices with an MDM or MAM system, which let you delete the Tableau Mobile app along with all of its offline content.
Disable offline previews for a site
By default, offline previews are enabled for all sites. But if you're a Tableau administrator, you can disable offline previews for specific sites, preventing favourite workbooks and views from being stored on users’ devices. When offline previews are disabled, Tableau Mobile displays favourites only as low-resolution thumbnail images, obscuring details about data.
In a web browser, sign in to your server and site as an administrator. (At the top, make sure the site name appears.)
Under Offline Favourites for Tableau Mobile, clear Enable offline favourites.
Note: If your organisation uses the latest version of Tableau Mobile, individual users can also disable offline previews in the app settings(Link opens in a new window).
Optimise client-side rendering with Tableau Server
If you're a Tableau Server administrator, you can optimise performance by controlling when views are rendered on the server instead of mobile devices. The choice depends on the complexity of a view, which is determined by the number of marks, rows, columns and more. If a view is less complex, it's faster for mobile devices to render the view. If a view is more complex, it's faster to send a request to Tableau Server and take advantage of the server's greater computing power.
As a server administrator, you can configure when client-side rendering happens on mobile devices by adjusting the complexity threshold. For example, you might lower the threshold for mobile devices if you notice that views display slowly on them. Or, you might increase the threshold to reduce the number of requests to Tableau Server.
By default, the complexity threshold for mobile devices is 60. To adjust the complexity threshold, enter the following in the command-line interface for Tableau Services Manager:
tsm configuration set -k vizqlserver.browser.render_threshold_mobile -v [new value]
For example, to change the mobile threshold to 40, you would enter the following command:
tsm configuration set -k vizqlserver.browser.render_threshold_mobile -v 40
For more information, see these topics in Tableau Server Help: