Query span timestamps and calculate deltas | Sentry Community | Page 1

frosty fox Dec 3, 2025, 11:20 PM

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Hi all,

I’m trying to measure the latency between two spans (a parent span and child span) in our Bun SDK setup.

Both spans already appear in Traces, share the same trace_id, and from what i see in the sdk have their own timestamp fields. All I want is to aggregate the delta:

child.start_timestamp – parent.start_timestamp (p50/p95 across all traces).

I can’t find any way in Discover (transactions is being deprecated) or the Traces dashboard to calculate this. The UI only shows per-trace waterfalls, no start-offset column, and no way to aggregate percentiles. Metrics aren’t available in the Bun SDK, so I can’t emit this as a distribution metric either.

I know I can add custom timestamp attributes in my Sentry.startSpan() calls, but the timestamps already exist on the spans. The problem is simply that I can’t query the relationship. Am i missing anything obvious in how to use the traces dashboard to view this data?

Thanks!

frosty fox Dec 4, 2025, 1:03 AM

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nevermind, looks like this isn't supported and I should just use custom span attributes: https://github.com/getsentry/sentry/issues/98090

GitHub

Feature Request: Visualize Time Difference Across Spans (End–Star...

Problem Statement We’ve recently created a new dashboard for one requirement and we are adding custom spans to our traces (for example, spans A, B, and C) and are using the dashboard to visualize t...

rotund field Dec 4, 2025, 3:05 AM

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Feel free to leave a comment about your use case @frosty fox. We query on comments/GH upvotes when planning new features

frosty fox Dec 4, 2025, 3:13 AM

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@rotund field just one question: is there any public start_timestamp field on a Span via getActiveSpan()? i would like to avoid prop drilling the parent spans' start time through my codepath

#Query span timestamps and calculate deltas