I’m playing around with Kapacitor and having a hard time understanding how Retention Policies in InfluxDB have an impact on a stream. The stream seems to effectively be relaying data from InfluxDB to Kapacitor so Kapacitor can monitor the stream of incoming data and look for exceptions/out-of-bound conditions. I notice that retention policies feature prominently both in the subscription and in how Kapacitor binds to said subscription, so it makes me wonder - why does it matter?
If a retention policy specifies that data older than 1 year is removed from InfluxDB, how does that impact the real-time push of data out of InfluxDB?
Can retention policies on the Kapacitor InfluxDBsubscription improve or harm performance?