AppSignal - Metrics
08 Feb 2019collection
https://docs.appsignal.com/appsignal/request-lifecycle.html
After your application serves the request, the transaction is closed and placed into a queue. Depending on your environment (development/production) and the gem version, the thread that was started during the application start sleeps a certain amount of time. Once the sleep is over it processes the queue of transactions and sends it to our AppSignal Push API.
custom metrics are not sent immediately - they must be buffered by agent during some amount of time (most likely 1 minute) and only then are they sent to AppSignal.
metric values are collected during this time frame (~1 minute) and then final value (or values) is sent to AppSignal - it depends on metric type what value is eventually persisted if helper is called multiple times:
- gauge: the latest value
- measurement: call count and average value
- counter: sum of counter values
for measurement metric both values are persisted - it creates 2 metric
fields (COUNT and MEAN) for them accordingly (4 metric fields in all).
display
metric type also determines what values are used for current display time frame in web UI - the same rules apply as when collecting metrics but now these rules apply to persisted values (not the values passed to helpers).
examples
- gauge: database size
- measurement: RPM and average response time
- counter: login count