Performance Issues

The Issue Details page for performance issues helps you to gain further insight into the source of an issue and the impact it has on your application's users. The main area of the page displays information about a specific transaction event that's part of an issue. The top panel and right-hand sidebar of the page display a summary of all the events grouped together in this issue:

Performance issue

While the Issue Details page displays information about a specific transaction event that's part of an issue, you can navigate between the events of an issue using the "Older" and "Newer" buttons. You'll see information about the issue as well as the details of the most recent event. You'll also be able to see the summary of when the issue was seen, a breakdown of the tags, span evidence, and breadcrumbs if they are available.

How Performance Issues Work

Sentry detects performance issues by scanning incoming transaction events. First we check various properties of the transaction (span durations, span arrangement, span types, and so on) to detect likely problems. We then check these properties against corresponding thresholds to determine whether a performance issue exists. Lastly, we generate a unique problem

fingerprintThe set of characteristics that define an event.
based on the problem type and location in the application, and use that fingerprint to create a performance issue.


Tags are key/value string pairs that are both indexed and searchable. For example, a tag provides you with information such as the browser, device, or user associated with the event. Tags are the diagnostic information sent by the SDK for the individual event.

The tags displayed in the main section of this page are specific to the event that you're viewing. In contrast, the tags displayed in the right-hand sidebar are a summary of all tag values for all events included in the issue. You can set your own tags to make them more useful for debugging as described in Customize Tags.

Span Evidence

Span evidence is information that explains the performance problem in the context of the current event. It may include details like the specific database queries that cause the problem, the spans that contain the problem, and the slow spans that have an impact on performance. This section also has a span tree which shows how the problematic spans relate to the rest of the event. Different performance problems will have slightly different kinds of evidence.

Performance Issue Limitations

Performance issues currently have the following limitations:

  • Sentry only detects one type of issue: N+1 Queries
  • You cannot create alerts for performance issues
  • Performance issues cannot be merged or deleted
  • Custom fingerprinting and grouping do not apply to performance issues
  • Performance issues only support simple ignore rules

We're working on removing some or all of these limitations.

Help improve this content
Our documentation is open source and available on GitHub. Your contributions are welcome, whether fixing a typo (drat!) to suggesting an update ("yeah, this would be better").