Dear all,
I have been incapacitated by the flu the last week - so I apologize for not responding to you suggestions before now.
Thank you so much every-body.
I'm up and running with my app using the advice from the community.
I have adopted the DBI / dbplyr / dplyr approach.
Even-though this speeds up the query I still have some waiting time before the final data is fetched after filtering server side.
During this waiting period, nothing happens, and I was wondering if there is a way to put a "please wait - fetching data" message or a spinning wheel until data has been fetched?
PS
Another key learning is to not used {r global} chunk option in my flex-dashboard as this simply does not work for me; whatever is put here will not be read again the next time the app is accessed through the web-site.