%Monitor class to collect and manage part of the Monitor History Database.
This class collects the SYS.History.PerfData samples for the Performance Metrics,
as defined in the Performance and WriteDaemon classes, at short intervals
(default of 30 seconds).
By default the SYS.History.PerfData collection is kept for 7 days and then
purged. The number of days to keep may be modified using SYS.History.PerfData:SetPurge()
The Detail samples can be automatically rolled up at the end of each day into
Hourly (SYS.History.Hourly) or Daily (SYS.History Daily) summaries, which can be
kept for longer periods.
Get the basic SYS.History.PerfData sample for the Monitor History Database.
This method also handles purging and accumulation of the Detail metrics
into the long term database (SYS.History.Hourly and SYS.History.Daily).
Initialize property values