> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rootprint.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Read a trace

> Open a trace from a log or by ID, read the waterfall and span details, and configure which log field carries the trace ID.

A trace opens as a waterfall of spans with a detail panel for the selected span. You arrive at a specific trace rather than browsing a list — see [Traces](/traces/overview#how-you-reach-a-trace) for the ways in.

## Open a trace

**From a log.** Open any log in the detail drawer. If the log carries a trace ID, a **Trace** tab appears alongside the other tabs, showing the waterfall inline. Click through for the full page.

**By trace ID.** Paste a trace ID — 32 hexadecimal characters — into the log search box. Rootprint recognizes it and opens that trace directly instead of running a search. Case does not matter here: the search box lowercases what you paste. An all-zeros ID falls through to a normal search, because OTLP writes that value on logs that carry no trace context.

**By URL.** A trace has a permanent address at `/traces/<traceId>`. Share it like any other link. The URL and `GET /api/traces/{traceId}` both take the canonical form only — exactly 32 lowercase hex characters, not all zeros — and reject anything else with `400`.

## The waterfall

Each span is a bar positioned by its start offset and sized by its duration. Spans are colored by service, so a request crossing four services is four colors. The root span's status is shown in the header, and spans that ended in an error are marked.

Selecting a span opens its detail panel.

## Span details

The detail panel has three tabs. A tab with nothing in it is disabled and skipped when you move between spans with the keyboard.

| Tab            | Contents                                                           |
| -------------- | ------------------------------------------------------------------ |
| **Overview**   | The span's name, service, timing, status, and its attributes.      |
| **Parameters** | Attributes the span carries as call parameters.                    |
| **Events**     | Timestamped events recorded on the span, each with its own fields. |

Two attributes are hidden from the panel because they restate the span's own error state, which the waterfall already shows: `otel.status_code` and `error`. `span.kind` and `otel.status_description` are kept — they carry information nothing else displays.

## Jump back to logs

A span links to the logs it produced, with a count. This is the reverse of opening a trace from a log: from a slow or failing span, you go straight to what that span logged.

When a trace's logs number 1,000 or more, Rootprint stops computing per-span counts and omits them; the trace-wide link back to logs still works.

## Truncated traces

A trace larger than 2,000 spans returns a subset, and the view says so. Because the underlying query is unsorted, the spans you get are an arbitrary subset rather than the first 2,000 by time — a truncated waterfall is not the beginning of the trace, it is a sample of it.

## Correlate logs with traces

Correlation in both directions depends on one per-index setting: **Trace ID field**.

| Setting            | Default    | What it controls                                             |
| ------------------ | ---------- | ------------------------------------------------------------ |
| **Trace ID field** | `trace_id` | The dot-notation path to the trace ID inside a log document. |

The default matches the OpenTelemetry log schema, so the bundled `otel-logs-v0_9` index needs no configuration. For a custom schema, set this to wherever your trace ID lives — for example `attributes.traceId` — on the index's **Configuration** tab under **Settings → Indexes**. See [Manage indexes](/configuration/manage-indexes#field-role-mappings).

Until this points at a real field, logs and traces stay unlinked: no **Trace** tab in the log drawer, and no log counts on spans.

## Related

* [Traces](/traces/overview)
* [Send traces](/traces/send)
* [Manage indexes](/configuration/manage-indexes#field-role-mappings)