# Metrics

Browse every OpenTelemetry metric Maple has received, then chart one with an aggregation, a filter, and a breakdown by attribute.

The **Metrics** page lists every metric Maple received in the selected time range, with its type, emitting service, and data point count. Open a metric to chart it: choose an aggregation, filter by attribute, break it down by a dimension, and add the chart to a dashboard or turn it into an alert.

## What data it needs

Metrics arrive over OTLP from an OpenTelemetry SDK or collector, or from a [Prometheus scrape target](/docs/integrations/prometheus). Maple stores four OTLP metric types:

| Type                  | Badge         | Examples                                        |
| --------------------- | ------------- | ----------------------------------------------- |
| Sum                   | **Sum**       | Request counters, bytes sent. Monotonic or not. |
| Gauge                 | **Gauge**     | Memory in use, queue depth.                     |
| Histogram             | **Histogram** | Request duration with explicit buckets.         |
| Exponential histogram | **Exp Hist**  | Request duration with exponential buckets.      |

OTLP Summary metrics are not stored. The Prometheus scraper converts summaries into sums and a quantile gauge before ingest.

The **Service** column and the service filter read the `service.name` resource attribute. Data point attributes become the dimensions you can filter and group by.

## Browse metrics

The default time range is the last 24 hours.

Four cards at the top count metrics by type: **Sum Metrics**, **Gauge Metrics**, **Histogram**, and **Exp Histogram**. Each shows its data point count and number of unique metrics. Click a card to filter the list to that type. Click it again to clear the filter.

<figure class="shot">
  <img src="/screenshots/docs/metrics-01-catalog.webp" alt="The Metrics page: four cards counting sum, gauge, histogram and exponential histogram metrics, a search box, and a grid of sparkline cards, one per metric, each labelled with its type and the services that emit it." loading="lazy" />
  <figcaption>The metric catalog in grid view. Click a type card to filter the list.</figcaption>
</figure>

Type in **Search metrics...** to filter by metric name. Switch between **Grid view** (a sparkline card per metric, the default) and **Table view**. The table, headed **Available Metrics**, has these columns: **Metric Name** (with its description), **Type**, **Service**, **Points**, and **Last Seen**. Click **Load more** to page through long lists.

Click a metric to open it.

## Chart a metric

The metric page has a chart, a breakdown panel, and a side panel of metadata.

Query controls above the chart:

| Control       | What it does                                                                                                                                                          |
| ------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Aggregate** | How data points combine per time bucket. Monotonic sums offer `rate` (the default), `increase`, and `sum`. Other types offer `avg`, `sum`, `min`, `max`, and `count`. |
| **Where**     | A filter on attributes, with autocomplete. For example `http.route = "/api/users"`.                                                                                   |
| **Group by**  | **Everything (no breakdown)**, `service.name`, or any data point attribute as `attr.<key>`.                                                                           |
| **Every**     | The bucket size in seconds. **Auto** picks one from the time range.                                                                                                   |

The chart header shows the query, such as `rate(http.server.requests) by service.name`, and the metric's unit.

The **Top values** panel ranks values of one attribute. Choose it with **Break down by...** (default `service.name`). Click a bar to add that value to **Where**.

The side panel shows the type, unit, and whether a sum is monotonic. It also shows **Datapoints in range**, **First seen**, **Last seen**, how many services emit the metric, and each attribute key with its usage count.

## Save and share

- **Add to dashboard** adds the chart to an existing dashboard, or creates one with **Create & add**.
- **Create alert** opens a new [alert rule](/docs/alerting/alert-rules) with this query filled in.
- **Copy link** copies a URL that restores the aggregation, filter, grouping, and step.

## Query metrics from an assistant

The [MCP server](/docs/reference/mcp) exposes the same data:

- `list_metrics`: search metrics by name, service, or type, with unit, monotonicity, and volume.
- `query_data` with `source=metrics`: a time series or breakdown for one metric, with the same aggregations and grouping by service or attribute.

## Troubleshooting

- **"No metrics found".** No metric matched the search, type, or time range. Clear the search and widen the range.
- **"No data for this metric in the selected range".** The metric exists but had no data points in this window. Widen the range, or check that the emitting service is still running.
- **A summary metric is missing.** OTLP summaries are dropped at ingest. Export histograms instead.
- **"Not enough datapoints for a preview".** The metric has too few data points in range to draw a sparkline. Open the metric to see its values.
- **Rates look wrong.** `rate` and `increase` apply to monotonic cumulative sums. For a gauge, use `avg` or `max`.

## Next steps

- [Build dashboards](/docs/dashboards/build-dashboards): combine metric charts with trace and log queries.
- [Prometheus scraping](/docs/integrations/prometheus): pull metrics from exporters.
- [Uptime monitoring](/docs/alerting/uptime-monitoring): alert on HTTP check metrics from the OpenTelemetry Collector.
- [Services](/docs/explore/services): latency and error metrics derived from traces.