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DOC-14292 Product Change- PR #149705 - release-25.3: tracing: add background execution tracer (+ debug zip export) #19935

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6 changes: 6 additions & 0 deletions src/current/_includes/v25.3/sidebar-data/troubleshooting.json
Original file line number Diff line number Diff line change
Expand Up @@ -112,6 +112,12 @@
"urls": [
"/${VERSION}/automatic-cpu-profiler.html"
]
},
{
"title": "Automatic Go Execution Tracer",
"urls": [
"/${VERSION}/automatic-go-execution-tracer.html"
]
}
]
}
4 changes: 4 additions & 0 deletions src/current/v25.3/automatic-cpu-profiler.md
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Expand Up @@ -45,3 +45,7 @@ Enabling the automatic CPU profile capture on a cluster will add overhead to the
- [P99 latency]({% link {{ page.version.version }}/ui-sql-dashboard.md %}#service-latency-sql-99th-percentile)
- P50 latency by creating a [custom chart]({% link {{ page.version.version }}/ui-custom-chart-debug-page.md %}) for the `sql.exec.latency-p50` metric
- [CPU usage]({% link {{ page.version.version }}/ui-hardware-dashboard.md %}#cpu-percent)

## See also

- [Automatic Go Execution Tracer]({% link {{ page.version.version }}/automatic-go-execution-tracer.md %})
57 changes: 57 additions & 0 deletions src/current/v25.3/automatic-go-execution-tracer.md
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@@ -0,0 +1,57 @@
---
title: Automatic Go Execution Tracer
summary: The automatic Go execution tracer can be used to gain fine-grained insight into goroutine scheduling, blocking events, garbage collection, and runtime activity.
keywords: go execution trace, go execution tracing, execution tracer, automatic execution tracer
toc: true
---

The automatic Go execution tracer allows operators and support engineers to investigate internal system behavior over time. Use this feature to gain fine-grained insight into goroutine scheduling, blocking events, garbage collection, and runtime activity.

{{site.data.alerts.callout_info}}
Execution tracing introduces a performance overhead. This feature is primarily intended for use under the guidance of [Cockroach Labs Support](https://support.cockroachlabs.com/).
{{site.data.alerts.end}}

When enabled, the automatic Go execution tracer captures runtime execution traces on a recurring schedule and stores them in the node's log directory. These traces are collected in the background and can be analyzed using Go’s standard tooling (e.g., [`go tool trace`](https://pkg.go.dev/runtime/trace)).

To prevent disk overuse, older traces are automatically garbage collected based on a configurable storage limit.

## Configuration

You can configure automatic Go execution trace capture with the following [cluster settings]({% link {{ page.version.version }}/cluster-settings.md %}):

Cluster Setting | Description | Default Value
----------------|-------------|---------------
`obs.execution_tracer.interval` | Enables periodic execution tracing on each node and defines how often traces are collected. Set to a positive duration (e.g., `10m`, `1h`) to enable. Set to `0` to disable (default). | `0`
`obs.execution_tracer.duration` | Sets how long each execution trace runs. Use short durations (e.g., 5-15 seconds) to produce traces that are easier to analyze. | `10s`
`obs.execution_tracer.total_dump_size_limit` | Sets a soft limit on the total disk space used by execution trace files. When the limit is exceeded, the oldest files are deleted. | `4GiB`

## Accessing Go execution traces

- The automatic Go execution tracer saves the captured traces to disk on each node's file system in the [logging directory]({% link {{ page.version.version }}/configure-logs.md %}#logging-directory). The default path is `cockroach-data/logs/executiontrace_dump`.
- To access these Go execution traces, you must use the node file system.
- Each file represents a single trace session, includes the `executiontrace.` prefix and `.out` extension, and is timestamped to support correlation with other logs and profiles. For example, the trace file could be named `executiontrace.2025-07-14T18_41_22.216.out`.
- Enabling the automatic Go execution tracer does add Go execution traces to [debug zips]({% link {{ page.version.version }}/cockroach-debug-zip.md %}) in the `nodes/*/executiontrace` paths.

## Best Practices

- Trace duration should be short (e.g., 5s–15s). Shorter trace files are easier to parse and load into external tools.
- Storage limit should be generous to allow sufficient trace history. Avoid overly tight disk caps unless necessary.
- Enable tracing temporarily when troubleshooting runtime behavior or under support guidance, as it may slightly impact performance.

## Performance Impact

Enabling execution tracing incurs a low overhead, estimated at 1–2% based on upstream Go benchmarks ([Go blog, 2024](https://go.dev/blog/execution-traces-2024#low-overhead-tracing)). No additional CockroachDB-specific benchmarks are available at this time.

## Example

To enable 10-second traces every 15 minutes with a storage limit of `8GiB`, configure the following settings:

```sql
SET CLUSTER SETTING obs.execution_tracer.interval = '15m';
SET CLUSTER SETTING obs.execution_tracer.duration = '10s';
SET CLUSTER SETTING obs.execution_tracer.total_dump_size_limit = '8GiB';
```

## See also

- [Automatic CPU Profiler]({% link {{ page.version.version }}/automatic-cpu-profiler.md %})
1 change: 1 addition & 0 deletions src/current/v25.3/troubleshooting-overview.md
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Expand Up @@ -33,3 +33,4 @@ If you experience an issue when using CockroachDB, try these steps to resolve th
- [`cockroach debug zip`]({% link {{ page.version.version }}/cockroach-debug-zip.md %})
- [`cockroach debug tsdump`]({% link {{ page.version.version }}/cockroach-debug-tsdump.md %})
- [Automatic CPU Profiler]({% link {{ page.version.version }}/automatic-cpu-profiler.md %})
- [Automatic Go Execution Tracer]({% link {{ page.version.version }}/automatic-go-execution-tracer.md %})
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