Hello Sekhar Gudhati,
I will move this question to Server Administration where other Tableau Server Admins contribute and assist with forum questions. It would help to know what you are trying to do as it relates to 'tuning'. Is there something you are trying to accomplish with the published data source specifically?
Yes, I want to know how the data gets retrieved to the report from a published data source , for suppose if I use a live connection to oracle data source then the language used is Oracle ,Similarly how that happens from a published data source ? and how can we tune them ?
Suppose if I built index on a particular column ,extract the data and publish to the server. Now the report uses published data source for customizing the views, Does the index have any effect on customizing the views faster ? if so how?
Thanks in advance
Tableau uses in-memory fast Data engine that does your calculations and retrieves the data from the source. The process dataserver.exe is responsible for Managing connections data sources while the data engine tdeserver64.exe fetches the data and does all the calculations needed.
Take a read at this http://www.tableau.com/sites/default/files/pages/tcc11-fastdataengine.pdf to find out more on how tableau is designed to consume data and how you can optimize it for your data loads.