> NOTE: If you're not seeing the `Data Sources` link in your side menu it means that your current user does not have the `Admin` role for the current organization.
| _Custom Query Parameters_ | Add custom parameters to the Prometheus query URL. For example `timeout`, `partial_response`, `dedup` or `max_source_resolution`. Multiple parameters should be concatenated together with an '&'. |
| _Query expression_ | Prometheus query expression, check out the [Prometheus documentation](http://prometheus.io/docs/querying/basics/). |
| _Legend format_ | Controls the name of the time series, using name or pattern. For example `{{hostname}}` will be replaced with label value for the label `hostname`. |
| _Min step_ | Set a lower limit for the Prometheus step option. Step controls how big the jumps are when the Prometheus query engine performs range queries. Sadly there is no official prometheus documentation to link to for this very important option. |
| _Resolution_ | Controls the step option. Small steps create high-resolution graphs but can be slow over larger time ranges, lowering the resolution can speed things up. `1/2` will try to set step option to generate 1 data point for every other pixel. A value of `1/10` will try to set step option so there is a data point every 10 pixels. |
| _Metric lookup_ | Search for metric names in this input field. |
| _Format as_ | Switch between Table, Time series or Heatmap. Table format will only work in the Table panel. Heatmap format is suitable for displaying metrics having histogram type on Heatmap panel. Under the hood, it converts cumulative histogram to regular and sorts series by the bucket bound. |
| _Instant_ | Perform an "instant" query, to return only the latest value that Prometheus has scraped for the requested time series. Instant queries return results much faster than normal range queries. Use them to look up label sets. |
The Prometheus datasource allows you to run "instant" queries, which queries only the latest value.
You can visualize the results in a table panel to see all available labels of a timeseries.
Instant query results are made up only of one datapoint per series but can be shown in the graph panel with the help of [series overrides](/features/panels/graph/#series-overrides).
To show them in the graph as a latest value point, add a series override and select `Points > true`.
To show a horizontal line across the whole graph, add a series override and select `Transform > constant`.
> Support for constant series overrides is available from Grafana v6.4
Checkout the [Templating]({{< relref "../../reference/templating.md" >}}) documentation for an introduction to the templating feature and the different
For details of _metric names_, _label names_ and _label values_ are please refer to the [Prometheus documentation](http://prometheus.io/docs/concepts/data_model/#metric-names-and-labels).
It's possible to use some global built-in variables in query variables; `$__interval`, `$__interval_ms`, `$__range`, `$__range_s` and `$__range_ms`, see [Global built-in variables](/reference/templating/#global-built-in-variables) for more information. These can be convenient to use in conjunction with the `query_result` function when you need to filter variable queries since
Make sure to set the variable's `refresh` trigger to be `On Time Range Change` to get the correct instances when changing the time range on the dashboard.
**Example usage:**
Populate a variable with the the busiest 5 request instances based on average QPS over the time range shown in the dashboard:
```
Query: query_result(topk(5, sum(rate(http_requests_total[$__range])) by (instance)))
Why two ways? The first syntax is easier to read and write but does not allow you to use a variable in the middle of a word. When the _Multi-value_ or _Include all value_
- A Prometheus query for pending and firing alerts (for details see [Inspecting alerts during runtime](https://prometheus.io/docs/prometheus/latest/configuration/alerting_rules/#inspecting-alerts-during-runtime))
Since 4.6.0 Grafana exposes metrics for Prometheus on the `/metrics` endpoint. We also bundle a dashboard within Grafana so you can get started viewing your metrics faster. You can import the bundled dashboard by going to the data source edit page and click the dashboard tab. There you can find a dashboard for Grafana and one for Prometheus. Import and start viewing all the metrics!
It's now possible to configure data sources using config files with Grafana's provisioning system. You can read more about how it works and all the settings you can set for data sources on the [provisioning docs page](/administration/provisioning/#datasources)
