About
This page is about metrics as telemetry data context (realtime performance, monitoring of system)
A telemetry metric is a time serie with:
- timestamped
- numerical value
- and optional labels
Other name
Monitoring Metrics are also known as:
- Statistical Collector
- Perfcounter (generally on Windows)
- Performance metrics
- Performance data
They are known as statistical data collectors because they gather data and compute statistics. They are used to collect, evaluate and report results, e.g.
- mean residence times of customers
- or the average utilisation of a server.
Aggregated metrics / Statistics
An aggregated metrics is
- calculated from time serie data.
- a statistic(s) (See also the page Counter - Statistics (for Engineers on operational data))
They are event metrics.
For the business related view of metrics, see Dimensional Data Modeling - Metrics - Key Performance indicators (KPI)
Type
Counter
A Counter is a metric that:
- can go only up.
- is reset when the application restarts.
- is used to record occurrences of events like the number of customer arrivals
- is plotted with a rate function over an interval
Car example: the mileage counter.
Gauge
A Gauge is a metric that can go up and down (gauge values are not rates).
Car Example: Speedometers
Timer
A Timer measures both the count of timed events and the total time of all events timed.
Others
- Histogram - A histogram ranks the measured values into predefined classes.
- Regressions: A Regression perform a regressional analysis of two different collected value series (x and y). It reports the number of observations, mean (for x and y), regression and correlation coefficients, standard deviations and interception.
Time series:
- Tallies. A tally records the mean and standard deviation of a (time) series of values. Example: Computing the average time customers spent on a system
- Accumulates: An Accumulate records the mean and standard deviation of a time series of values against different time intervals. Example: System load
See also: Prometheus Metrics Type
Implementation
- Statistical Data Collectors (desmoj.core.statistic package)