When you run a report or a dashboard, Urungi calculate every SQL query every time. Sometimes it's not needed because the results are valid for minutes (or hours or days)
Proposal : when you create a report, have an option saying "results are valid for ___ minutes". If ___ > 0, then store the results in a JSON. If the report is re-run, check if the cache validity, and, if still valid, use the JSON in cache instead of running the SQL again.
PS : below the field (or as a hint), remind that 1 day = 1440mn