Caché Monitoring Guide - InterSystems Documentation

Summaries
11.3 Summaries
The %Monitor.System.HistoryPerf and %Monitor.System.HistorySys classes, as executed by the %MONAPP process, also
create the hourly and daily summaries at the end of each day. The summaries are defined as the persistent classes
SYS.History.Hourly and SYS.History.Daily; they include all four of the base classes as embedded objects.
For each metric property, the system may calculate the average, maximum (high-water mark), standard deviation, minimum,
median, or total for each hour and for the whole day. The summary functions are selectable (or may be disabled) for each
base class (SYS.History.Performance, SYS.History.WriteDaemon, SYS.History.SystemUsage, or SYS.History.Database) and
for each summary period class, using the SetSummary() method of each of the base classes. By default, the History
Monitor calculates average, maximum and standard deviation for each class for both hourly and daily summaries.
Note:
The counter properties of the SYS.History.Performance class are normalized to per second rates for these calculations
(except Total).
Purging Data
After creating the summaries, the %MONAPP process automatically purges the interval and hourly databases. The default
is seven (7) days for interval data and 60 days for hourly data, but these may be changed using the SetPurge() method in
SYS.History.PerfData and SYS.History.Hourly classes. The SYS.History.Daily data is not automatically purged, but can be
done manually using the SYS.History.Daily:Purge() method.
11.4 Accessing the Data
Since the database is defined as persistent classes, the data is available using standard SQL or persistent object access.
Using the SQL browser in the Management Portal is a quick and easy way to see the various SQL schemas/tables that are
created, including the individual property values.
There are several basic queries implemented in each of the persistent classes in SYS.History (SYS.History.PerfData,
SYS.History.SysData, SYS.History.Hourly, and SYS.History.Daily) that can be used to access the individual tables for a date
range; for more information about the queries, see the class reference documentation.
The are also several Export() methods provided for each persistent class so that the individual tables can be exported to
files in CSV format, suitable for use with a spreadsheet such as Microsoft Excel. In particular, the
SYS.History.PerfData:Export() method creates a file that is very similar in format to that created by the ^mgstat utility
(for more information, see the “Monitoring Performance Using ^mgstat” chapter of this guide).
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