Will it make sense for you to see Last update or say refresh time of your data source ?
I mean if your data is changing frequently say every min or so then below method will be effective for you.
Hi Ritesh, thanks for your comments. My data does not change often but it's a requirement that we have a ETL run every hour. I want the date time stamp of the TDE data source last updated or overwritten because If someone updates a value in DB and refreshes the tableau report it will not be reflected because the ETL run only every hour. That's why in our title we need to say "This data source was last updated on <<DateTime>>"
I am talking about Changes during ETL not at Transactional DB.
If your ETL process is by any chance updating the timestamp of upload (during ETL )
So, if you make use of that time-stamp indirectly you are getting the Tableau Extract Time.
For example if there is a column as LAST_UPDATE that would save the time of upload then you can make use of max (LAST_UPDATE).
ETL timings ---> 12 am 1am 2 am 3 am -------->
Tableau refresh ---> 2:30 am every day
So if you have set Tableau extract refresh at say 2:30 am and if the extract is refreshed successfully then the time will be displayed as 2 am which is not a bad information either.
Other benefit is that you will also know the last time of successful ETL refresh via Tableau , if 2 am ETL refresh was a failure Tableau will show 1 am which is a good information to have.
Suppose if you had failed ETL refresh at 2am and successful Tableau Extract at 2:30 am but then you are displaying Tableau extract refresh time , it will come up as 2:30 am.
May be in your case it is mandatory to have the other way , just expressing my views