Tableau is a "read-mostly" analytical application, and the only writes Tableau ever does is to a temporary table. Tableau will use a temporary table to accelerate performance in certain circumstances, but the contents of the temporary table are typically very small compared to the original data set size. One way to prevent Tableau from using temporary tables altogether is to revoke user permissions for creating temporary tables, which forces Tableau to find other ways to formulate and optimize queries.
You can learn a lot more about why Tableau generates the kinds of queries it does -- including several points involving temporary tables -- at the following webpage containing session materials from the 2011 Tableau Customer Conference. Tableau Customer Conference 2011: Advanced Applications. View the video or slide deck for the first topic, named "Tuning Tableau and Your Database for Great Performance - Matt Higgins & Robert Morton".
Thank you for pointing the Customer Conference 2011 ressources. These are very valuable information that helped me understand how Tableau uses temporary tables, and how I can optimize Tableau and my database for better performance.
Thank you !
I'm glad to help!