Are you talking about extract refreshes? On desktop, it's pretty much manual. On server, you can setup a schedule at the appropriate frequency (e.g. hourly, daily, weekly) and then attach the workbook to be refreshed using this schedule.
I have live connection to db.
The server setting that you're referring to is global across your deployment. However, you could change it to refresh less often (always get from cache) and then the ones that need to always go live against the data you could append "?:refresh=yes" to the URL. Not sure if this is an option. A workaround that we've come up with is to create a dashboard within the viz that the user is picking, and then within the dashboard, insert a web object url and within the url point at the workbook that you want to always refresh live by appending the refresh=yes
I think this is what you are looking for.
If you like the idea of cache configuration at the workbook level please vote for the idea. Also comment on the idea to set cache configuration at the data source level.