Resolution

• As a first step, review ​Performance Tips in Tableau Help. 
• Simplify your workbooks where possible. The process of parameter and calculation validation takes more time and resources in workbooks that contain a large number of worksheets, dashboards, calculations, and parameters.
• If you are using Custom SQL in your data connection, try creating a materialized view directly in your database instead. For more information, see Using Stored Procedures and Functions.
• See the Related Links section for additional performance information for both Tableau Desktop and Tableau Server.