public class ConfluenceUsageInfoInstrumentProvider
Main class which provide Confluence usage statistic via Instrument. Currently, we don't have anyway to get accurate data except DB call.
So now, I will query data and put it into cache which will expire after 10 mins. If JMX is enable then within 5 mins we only have 1 single DB call
(which I think not so bad because we have 2 conditions someone continuously get cache and we don't have any value in cache ).
Another note that we only expose instruments after we have DB available.