The Context Filter is not frequently changed by the user—if the Filter is changed, the database must be recomputed and the temporary table has to be rewritten, slowing performance.
When we set a dimension to context, Tableau creates a temporary table that will require a reload each time the view is initiated. For Excel, Access, and text data sources, the temporary table created is in an Access table format. For SQL Server, MySQL, and Oracle data sources, we must have permission to create a temporary table on our server. For a multidimensional data source, or cubes, temporary tables are not created, and Context Filters defined which Filters are independent and which are dependent.
