OK, I can’t understand the refresh logic correctly 
Searched almost related topics, documentation.
So I have a query which set to refresh every 5 minutes, made alerts based on this and plotted on a dashboard. Everything until this worked.
But my dashboard never refreshed the queries even though I set them to update every 5 min. Then from one of the support posts, I found out that adding a refresh=valueinseconds parameter to refresh the public dashboard.
Now, the dashboard refreshes every X minute (30 in my case). However, now the query which was set to refresh every 5 mins is not refreshing however the dashboard refreshes every query at 30m. Due to this the alerts are not triggering.
So is there a way to refresh the queries on the public dashboard based on the settings in the query along with honouring the complete dashboard refresh on every 30 minutes?
Also, what happens when a query-based on drop-down is plotted in the dashboard? I have set it to refresh every X minutes, but this seems not working. Is this because the query can’t run since a default parameter is not set from the dropdown or is there a way to set the default parameters when plotting on a public dashboard?