Troubleshoot Slow Tableau Server Workbooks

Scenario

You are supporting a business intelligence workbook that analysts build and validate in Tableau Desktop, but it becomes slow after publishing to Tableau Server. The same filters, calculations, and data source behave differently once the workbook is scheduled, refreshed, and viewed by multiple users. You need to isolate whether the slowdown comes from the data source, workbook design, extract refreshes, or server-side execution.

Question

Explain how you would troubleshoot a workbook that performs well in Desktop but slowly in Tableau Server.