diff --git a/docs/querying/basics.md b/docs/querying/basics.md index 1c72adb3e..304c9f07d 100644 --- a/docs/querying/basics.md +++ b/docs/querying/basics.md @@ -8,9 +8,15 @@ sort_rank: 1 Prometheus provides a functional query language called PromQL (Prometheus Query Language) that lets the user select and aggregate time series data in real -time. The result of an expression can either be shown as a graph, viewed as -tabular data in Prometheus's expression browser, or consumed by external -systems via the [HTTP API](api.md). +time. + +When you send a query request to Prometheus, it can be an _instant query_, evaluated at one point in time, +or a _range query_ at equally-spaced steps between a start and an end time. PromQL works exactly the same +in each cases; the range query is just like an instant query run multiple times at different timestamps. + +In the Prometheus UI, the "Table" tab is for instant queries and the "Graph" tab is for range queries. + +Other programs can fetch the result of a PromQL expression via the [HTTP API](api.md). ## Examples @@ -94,9 +100,7 @@ Examples: ## Time series selectors -Time series selectors are responsible for selecting the times series and raw or inferred sample timestamps and values. - -Time series *selectors* are not to be confused with higher level concept of instant and range *queries* that can execute the time series *selectors*. A higher level instant query would evaluate the given selector at one point in time, however the range query would evaluate the selector at multiple different times in between a minimum and maximum timestamp at regular steps. +These are the basic building-blocks that instruct PromQL what data to fetch. ### Instant vector selectors