You are asking for a real time refresh or like when ever user reopens the dashboard the data should be visible?
I am looking for real time refresh of data in Dashboard when there is any changes at the back end tables,
Even though the user is viewing the dashboard and changes happens in the tables, the dashboard should be refreshed for the data change.
without forcing user to refresh the dashboard or refreshing the dashboard at certain intervals of time.
You want to run a sql and get the latest timestamp from the table and wants the dashboard to refresh .
Two different things . one is a browser request (refresh the page) . one is a server request (checking for the results). Both cannot be done at a same place
But you can use apex for calling the sql code and ajax to call that code from the java script and based on that the refresh happens
Thats my view and i hope defenetlyothers has a better solution for this .
Let us know if it works for you