Hands-On Infrastructure Monitoring with Prometheus

Instant vectors

Instant vector selectors are named as such because they return a list of samples, relative to the query evaluation time, for the time series that match them. This list is called an instant vector, as it's a result at a given instant.

A sample is a data point of a time series, composed of a value and a timestamp. This timestamp, in most cases, reflects the time when the scrape occurred and that value was ingested, with the exception of metrics pushed to the Pushgateway, which, due to their nature, will never have timestamps. However, if functions are applied or operations are performed on the time series, the timestamp for the instant vector samples will reflect the query time and not the ingested time.

The way instant vectors ...