feat: add reverse span links, show span link detail by karl-power · Pull Request #3011 · hyperdxio/hyperdx

karl-power · 2026-08-27T13:27:39Z

Summary

Span links were only usable from the consumer side: a span showed the links it carries, as bare "Open trace" actions. There was no way to start from a producer span and find the consumer spans that link back to it.

New "Linked from" section in the span Overview panel listing spans whose links reference the selected span. Each entry shows the referencing span's name, service, duration, and timestamp, with the same open-trace navigation as forward links.
The existing Span Links section now resolves each link's target span and shows the same details instead of a bare "Open trace" action (which remains the fallback when the target can't be found).
Since forward and reverse links come in pairs, clicking a link that targets the span you just hopped from pops back to the previous breadcrumb instead of growing the trail forever on A ↔ B hops. SourceFrame gains an optional, source-agnostic originRowId for this.
Both lookups run through useQueriedChartConfig bounded to a time window anchored on the selected span, skewed in the direction links point in time: referencing spans run at/after the span (−1h/+24h), linked-to spans ran at/before it (−24h/+1h).

Screenshots or video

Untitled.mov

How to test on Vercel preview

Preview routes: /search

Steps:

Find a span that has some links (search Links.SpanId != [])
Open the span and scroll to the span link section, navigate to the linked span.
Check the reverse linking on the linked to span, as shown in the video.

References

Linear Issue: Closes HDX-5042
GitHub Issue: Closes [Feature Request] Show span links from the producer side too #2828
Related PRs:
- feat(traces): surface span links in the trace viewer #2463
- fix: show spans referencing the current span (#2828) #2868

changeset-bot · 2026-08-27T13:27:45Z

🦋 Changeset detected

Latest commit: b8819a4

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@hyperdx/app	Minor
@hyperdx/api	Minor
@hyperdx/otel-collector	Minor

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vercel · 2026-08-27T13:27:46Z

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Project	Deployment	Actions	Updated (UTC)
hyperdx-oss	Ready	Preview	Aug 27, 2026 1:48pm
hyperdx-storybook	Ready	Preview	Aug 27, 2026 1:48pm

github-actions · 2026-08-27T13:28:11Z

🟡 Tier 3 — Standard

Introduces new logic, modifies core functionality, or touches areas with non-trivial risk.

Why this tier:

Diff size: 661 production lines changed (Tier 2 max: < 250)

Review process: Full human review — logic, architecture, edge cases.
SLA: First-pass feedback within 1 business day.

Stats

Production files changed: 6
Production lines changed: 661 (+ 838 in test files, excluded from tier calculation)
Branch: reverse-span-links
Author: karl-power

To override this classification, remove the review/tier-3 label and apply a different review/tier-* label. Manual overrides are preserved on subsequent pushes.

greptile-apps · 2026-08-27T13:31:02Z

Greptile Summary

The PR adds reverse span-link discovery, resolves linked-span metadata, and improves navigation between mutually linked spans.

Adds bounded queries for forward and reverse span relationships.
Displays linked span names, services, durations, and timestamps in the overview panel.
Tracks origin row IDs to collapse reciprocal link hops back into the existing breadcrumb.
Adds focused component, query, and navigation tests.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
packages/app/src/components/linkedSpans.tsx	Adds shared query construction, result normalization, hooks, and metadata rendering for forward and reverse span links.
packages/app/src/components/DBRowOverviewPanel.tsx	Integrates resolved forward-link details and the new reverse-link section into the row overview.
packages/app/src/components/DBRowSidePanel.tsx	Adds origin-aware source-frame navigation so reciprocal span-link hops return through the existing breadcrumb.
packages/app/src/components/SpanLinksSubpanel.tsx	Enhances forward links with resolved span names and metadata while preserving the unresolved fallback.
packages/app/src/components/SpanLinkedFromSubpanel.tsx	Adds the reverse-link list UI and its trace-navigation actions.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  A[Selected span] --> B[Resolve forward links]
  A --> C[Query spans linking back]
  B --> D[Linked span details]
  C --> E[Linked from details]
  D --> F[Open linked trace]
  E --> F
  F --> G{Targets origin row?}
  G -->|Yes| H[Pop breadcrumb]
  G -->|No| I[Push source frame]

_{Reviews (3): Last reviewed commit: "feat: add reverse span links, show span ..." | Re-trigger Greptile}

github-actions · 2026-08-27T13:35:51Z

E2E Test Results

✅ All tests passed • 320 passed • 1 skipped • 1185s

Status	Count
✅ Passed	320
❌ Failed	0
⚠️ Flaky	3
⏭️ Skipped	1

Tests ran across 4 shards in parallel.

View full report →

github-actions · 2026-08-27T13:42:08Z

Deep Review

✅ No critical issues found. The feature is wired correctly end-to-end: useRowData projects the trace/span-id and __hdx_timestamp_value_* aliases the new hooks depend on, so linkAnchorDate resolves and both lookups fire. SQL is built with SqlString.format parameterization over trace/span ids and SqlString.raw only over source-configured column expressions (config, not user input), so no injection is introduced. Result rendering is wrapped in an ErrorBoundary, rows are deduped, and the selected span is excluded from its own reverse-link list. When no usable timestamp anchor exists the queries are disabled and the forward "Span Links" section still renders its prior bare "Open trace" fallback, so there is no regression to existing behavior.

Note on coverage: of the dispatched fan-out, the performance and previous-comments reviewers returned before synthesis was required; the remaining personas did not report back in time, so the findings below come from those two reviewers plus direct verification of the correctness, security, and navigation-state paths. Treat P0/P1 absence as verified for the paths inspected, not as a full-fan-out clearance.

🔵 P3 nitpicks (4)

packages/app/src/components/linkedSpans.tsx:150 — The reverse-link has()/arrayExists lookup is unindexed on the default ClickStack schema and getReverseSpanLinksConfig returns non-null for any trace span, so a full directional-window scan runs on every span-detail panel open even for spans with zero incoming links (unlike the forward lookup, which is gated on validSpanLinks.length > 0).
- Fix: Document the recommended Links.SpanId bloom_filter skipping index for operators, or gate/narrow the reverse window so the scan cost scales with intent.
packages/app/src/components/linkedSpans.tsx:166 — Both lookups silently cap at MAX_LINKED_SPANS = 50 (reverse keeps the earliest 50 by timestamp ASC; forward keeps the first 50 deduped pairs), so a span with more than 50 links shows a partial set with no truncation indicator.
- Fix: Surface a "showing first 50" affordance, or document the cap where the list renders so the omission is not silent.
packages/app/src/components/DBRowSidePanel.tsx:632 — The pop-back check compares the always-both-ids rowId against traceSpanRowId, which omits a clause when only one of the trace/span expression-or-value is present, so the reciprocal A↔B pop-back silently fails to fire in that partial case and the breadcrumb trail grows instead (no crash, benign degradation).
- Fix: Build rowId and traceSpanRowId from the same clause set so equality holds whenever both frames describe the same row.
packages/app/src/components/DBRowSidePanel.types.ts:44 — Typo somtimes in the originRowId doc comment.
- Fix: Correct to sometimes.

Reviewers (2 completed): performance, previous-comments — plus direct orchestrator verification of correctness, SQL-safety, and breadcrumb navigation state.

Testing gaps: No latency benchmark of the unindexed reverse has()/arrayExists scan against a large, default (unindexed) otel_traces table to confirm interactive panel-open cost at production scale.

pulpdrew

LGTM, and seems to work well.

Left a suggestion for another option if we're worried about the performance impact.

pulpdrew · 2026-08-27T18:59:29Z

+    ...(source.kind === SourceKind.Trace && source.serviceNameExpression
+      ? [
+          {
+            valueExpression: source.serviceNameExpression,
+            alias: LINKED_SPAN_ALIASES.SERVICE_NAME,
+          },
+        ]
+      : []),
+    ...(source.kind === SourceKind.Trace && source.durationExpression
+      ? [
+          {
+            valueExpression: getDurationMsExpression(source),
+            alias: LINKED_SPAN_ALIASES.DURATION_MS,
+          },
+        ]
+      : []),


nit: It might be nice to update some of these types to source: TTraceSource; so these checks aren't necessary, assuming we should typically only be working with trace sources in most of these functions.

pulpdrew · 2026-08-27T19:00:40Z

+  // (a scan of ~2 daily partitions). If that gets slow (~1B spans/day),
+  // adding to otel_traces:


Another option here is to gate this behind a button, say "Show spans linking to this span" in the UI to dispatch a potentially slow search, instead of always dispatching it when opening the panel

pulpdrew · 2026-08-27T19:07:46Z

+      // A link often points right back at the row one level up (forward and
+      // reverse span links come in pairs). Pop back to that breadcrumb instead
+      // of pushing an endless A <-> B trail. Only when no nav drilldown sits
+      // on top: popOne would pop the nav entry, not the source frame.


This is neat

pulpdrew · 2026-08-27T19:37:24Z

One other callout is that it may be good to add an E2E test for this functionality, to prevent regressions in the future.

github-actions Bot added the review/tier-3 Standard — full human review required label Aug 27, 2026

karl-power mentioned this pull request Aug 27, 2026

fix: show spans referencing the current span (#2828) #2868

Closed

greptile-apps Bot reviewed Aug 27, 2026

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Comment thread packages/app/src/components/linkedSpans.tsx

karl-power force-pushed the reverse-span-links branch from 9885865 to 5208e25 Compare August 27, 2026 13:35

vercel Bot deployed to Preview – hyperdx-storybook August 27, 2026 13:38 View deployment

vercel Bot deployed to Preview – hyperdx-oss August 27, 2026 13:39 View deployment

feat: add reverse span links, show span link detail

b8819a4

karl-power force-pushed the reverse-span-links branch from 5208e25 to b8819a4 Compare August 27, 2026 13:43

vercel Bot deployed to Preview – hyperdx-storybook August 27, 2026 13:46 View deployment

vercel Bot deployed to Preview – hyperdx-oss August 27, 2026 13:48 View deployment

karl-power requested review from a team and pulpdrew and removed request for a team August 27, 2026 14:12

pulpdrew approved these changes Aug 27, 2026

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		// adding to otel_traces:

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