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Trace viewer: scroll-load events past an auto-load cap#2200

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mitul-s merged 4 commits into
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ms/loading-spans
Jun 1, 2026
Merged

Trace viewer: scroll-load events past an auto-load cap#2200
mitul-s merged 4 commits into
mainfrom
ms/loading-spans

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@mitul-s mitul-s commented Jun 1, 2026

What

The new trace viewer was getting stuck on the first page for large runs. This re-wires pagination:

  • Auto-load up to a cap, then scroll-load. use-trace-viewer.ts backfills history pages until AUTO_LOAD_MAX_EVENTS (500), then stops; further loading is driven by scrolling.
  • IntersectionObserver scroll-loading. New useLoadMoreOnScroll + useIntersectionObserver hooks (ported from vercel/front's @vercel/hooks, with root threaded as a ref so the observer roots on the viewer's internal scroll container). A sentinel near the bottom of the span list triggers the next page — no per-scroll layout reads.
  • NewTraceViewer gains onLoadMore / hasMore / isLoadingMore props and renders a centered "Loading spans…" footer (Geist spinner) while fetching.
  • SplitPane exposes its scroll container via scrollContainerRef so the observer can root on it.

Notes

  • AUTO_LOAD_MAX_EVENTS is also set in vercel/front's use-workflow-trace-data.ts (the trace viewer's other consumer) — keep them in sync. See vercel/front#72039.
  • The cap governs only hands-free backfill; scroll + live-poll still load beyond it by design.

🤖 Generated with Claude Code

@mitul-s mitul-s requested a review from a team as a code owner June 1, 2026 16:49
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changeset-bot Bot commented Jun 1, 2026 •
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🦋 Changeset detected

Latest commit: 49f0c86

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

This PR includes changesets to release 16 packages
Name Type
@workflow/web-shared Patch
@workflow/web Patch
@workflow/cli Patch
workflow Patch
@workflow/world-testing Patch
@workflow/core Patch
@workflow/builders Patch
@workflow/next Patch
@workflow/nitro Patch
@workflow/vitest Patch
@workflow/astro Patch
@workflow/nest Patch
@workflow/rollup Patch
@workflow/sveltekit Patch
@workflow/vite Patch
@workflow/nuxt Patch

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karthikscale3
karthikscale3 reviewed Jun 1, 2026
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Review notes 1–6 (inline). Overall this fixes the missing pagination wiring; minor follow-ups above.

Comment thread packages/web-shared/src/components/new-trace-viewer/trace-viewer.tsx Outdated
Comment thread packages/web-shared/src/hooks/use-intersection-observer.ts
Comment thread packages/web/app/lib/client/hooks/use-trace-viewer.ts
Comment thread packages/web-shared/src/components/new-trace-viewer/trace-viewer.tsx Outdated
Comment thread packages/web/app/lib/client/hooks/use-trace-viewer.ts
Comment thread packages/web-shared/src/hooks/use-load-more-on-scroll.ts
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📊 Benchmark Results

📈 Comparing against baseline from main branch. Green 🟢 = faster, Red 🔺 = slower.

workflow with no steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
💻 Local 🥇 Nitro 0.041s (-4.4%) 1.006s (~) 0.965s 10 1.00x
💻 Local Express 0.043s (-3.8%) 1.005s (~) 0.962s 10 1.03x
💻 Local Next.js (Turbopack) 0.061s 1.005s 0.944s 10 1.48x
🐘 Postgres Nitro 0.062s (-35.2% 🟢) 1.013s (-2.8%) 0.952s 10 1.50x
🐘 Postgres Express 0.067s (+14.7% 🔺) 1.012s (~) 0.945s 10 1.61x
🐘 Postgres Next.js (Turbopack) 0.069s 1.013s 0.944s 10 1.68x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 0.277s (-32.4% 🟢) 2.111s (-15.9% 🟢) 1.834s 10 1.00x
▲ Vercel Express 0.316s (+34.0% 🔺) 2.418s (+13.2% 🔺) 2.102s 10 1.14x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Nitro | Express

workflow with 1 step

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
💻 Local 🥇 Express 1.093s (-2.8%) 2.006s (~) 0.913s 10 1.00x
💻 Local Nitro 1.101s (-2.7%) 2.006s (~) 0.905s 10 1.01x
🐘 Postgres Express 1.102s (-3.9%) 2.009s (~) 0.907s 10 1.01x
🐘 Postgres Nitro 1.105s (-3.0%) 2.010s (~) 0.904s 10 1.01x
💻 Local Next.js (Turbopack) 1.138s 2.006s 0.868s 10 1.04x
🐘 Postgres Next.js (Turbopack) 1.147s 2.009s 0.863s 10 1.05x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 1.672s (-10.8% 🟢) 3.778s (-0.8%) 2.105s 10 1.00x
▲ Vercel Nitro 1.744s (-55.2% 🟢) 3.467s (-41.3% 🟢) 1.723s 10 1.04x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

workflow with 10 sequential steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 10.523s (-3.2%) 11.019s (~) 0.496s 3 1.00x
💻 Local Nitro 10.529s (-3.8%) 11.021s (~) 0.492s 3 1.00x
🐘 Postgres Express 10.546s (-3.8%) 11.020s (~) 0.474s 3 1.00x
💻 Local Express 10.559s (-3.3%) 11.021s (~) 0.462s 3 1.00x
💻 Local Next.js (Turbopack) 10.776s 11.020s 0.244s 3 1.02x
🐘 Postgres Next.js (Turbopack) 10.826s 11.018s 0.191s 3 1.03x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 13.703s (-19.3% 🟢) 15.514s (-22.5% 🟢) 1.812s 2 1.00x
▲ Vercel Nitro 14.294s (-39.8% 🟢) 15.860s (-36.9% 🟢) 1.565s 2 1.04x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

workflow with 25 sequential steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
💻 Local 🥇 Express 13.734s (-8.3% 🟢) 14.025s (-6.7% 🟢) 0.292s 5 1.00x
🐘 Postgres Nitro 13.745s (-5.8% 🟢) 14.020s (-6.7% 🟢) 0.274s 5 1.00x
💻 Local Nitro 13.756s (-8.7% 🟢) 14.027s (-12.5% 🟢) 0.271s 5 1.00x
🐘 Postgres Express 13.893s (-4.7%) 14.220s (-5.3% 🟢) 0.327s 5 1.01x
💻 Local Next.js (Turbopack) 14.290s 15.029s 0.739s 4 1.04x
🐘 Postgres Next.js (Turbopack) 14.456s 15.018s 0.562s 4 1.05x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 23.240s (-53.8% 🟢) 25.296s (-51.9% 🟢) 2.056s 3 1.00x
▲ Vercel Nitro 23.351s (-63.8% 🟢) 25.318s (-62.0% 🟢) 1.966s 3 1.00x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

workflow with 50 sequential steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 12.370s (-11.7% 🟢) 13.016s (-10.8% 🟢) 0.646s 7 1.00x
🐘 Postgres Nitro 12.464s (-10.8% 🟢) 13.018s (-9.0% 🟢) 0.554s 7 1.01x
💻 Local Nitro 12.480s (-25.6% 🟢) 13.024s (-23.5% 🟢) 0.544s 7 1.01x
💻 Local Express 12.500s (-24.7% 🟢) 13.025s (-23.5% 🟢) 0.525s 7 1.01x
💻 Local Next.js (Turbopack) 13.513s 14.028s 0.515s 7 1.09x
🐘 Postgres Next.js (Turbopack) 14.052s 14.449s 0.396s 7 1.14x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 32.042s (-92.4% 🟢) 33.957s (-92.0% 🟢) 1.916s 3 1.00x
▲ Vercel Express 33.574s (-72.3% 🟢) 36.447s (-70.5% 🟢) 2.873s 3 1.05x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Nitro | Express

Promise.all with 10 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 1.177s (-7.7% 🟢) 2.008s (~) 0.831s 15 1.00x
💻 Local Express 1.179s (-20.8% 🟢) 2.006s (~) 0.828s 15 1.00x
🐘 Postgres Express 1.179s (-6.5% 🟢) 2.008s (~) 0.829s 15 1.00x
💻 Local Nitro 1.188s (-27.2% 🟢) 2.006s (-3.3%) 0.818s 15 1.01x
🐘 Postgres Next.js (Turbopack) 1.253s 2.008s 0.755s 15 1.06x
💻 Local Next.js (Turbopack) 1.357s 2.006s 0.648s 15 1.15x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 2.639s (-6.4% 🟢) 4.240s (-1.9%) 1.601s 8 1.00x
▲ Vercel Express 2.983s (+4.3%) 4.828s (+4.4%) 1.844s 7 1.13x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Nitro | Express

Promise.all with 25 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 1.239s (-47.3% 🟢) 2.008s (-33.3% 🟢) 0.769s 15 1.00x
🐘 Postgres Express 1.253s (-46.9% 🟢) 2.007s (-33.3% 🟢) 0.754s 15 1.01x
🐘 Postgres Next.js (Turbopack) 1.423s 2.007s 0.584s 15 1.15x
💻 Local Express 1.627s (-44.9% 🟢) 2.006s (-41.9% 🟢) 0.379s 15 1.31x
💻 Local Nitro 1.765s (-43.9% 🟢) 2.073s (-46.6% 🟢) 0.308s 15 1.42x
💻 Local Next.js (Turbopack) 1.886s 2.391s 0.506s 13 1.52x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 3.571s (-1.3%) 5.011s (-2.0%) 1.439s 6 1.00x
▲ Vercel Nitro 3.674s (-9.3% 🟢) 5.149s (-13.0% 🟢) 1.475s 6 1.03x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

Promise.all with 50 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 1.383s (-60.3% 🟢) 2.007s (-49.9% 🟢) 0.624s 15 1.00x
🐘 Postgres Nitro 1.390s (-60.0% 🟢) 2.008s (-49.9% 🟢) 0.618s 15 1.01x
🐘 Postgres Next.js (Turbopack) 1.724s 2.316s 0.592s 13 1.25x
💻 Local Express 4.388s (-47.4% 🟢) 4.868s (-46.1% 🟢) 0.480s 7 3.17x
💻 Local Next.js (Turbopack) 4.896s 5.297s 0.401s 7 3.54x
💻 Local Nitro 5.436s (-34.9% 🟢) 5.845s (-35.2% 🟢) 0.409s 6 3.93x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 5.577s (+58.2% 🔺) 7.509s (+35.7% 🔺) 1.932s 5 1.00x
▲ Vercel Express 6.337s (+49.4% 🔺) 8.535s (+39.3% 🔺) 2.199s 4 1.14x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Nitro | Express

Promise.race with 10 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 1.172s (-6.8% 🟢) 2.009s (~) 0.837s 15 1.00x
🐘 Postgres Express 1.184s (-5.8% 🟢) 2.008s (~) 0.824s 15 1.01x
🐘 Postgres Next.js (Turbopack) 1.241s 2.008s 0.767s 15 1.06x
💻 Local Next.js (Turbopack) 1.368s 2.006s 0.638s 15 1.17x
💻 Local Nitro 1.541s (-17.4% 🟢) 2.006s (-14.3% 🟢) 0.465s 15 1.31x
💻 Local Express 1.566s (-17.3% 🟢) 2.006s (-15.1% 🟢) 0.440s 15 1.34x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 2.817s (+9.1% 🔺) 4.521s (+3.9%) 1.704s 7 1.00x
▲ Vercel Nitro 2.821s (+14.7% 🔺) 4.519s (+8.4% 🔺) 1.698s 7 1.00x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

Promise.race with 25 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 1.250s (-46.5% 🟢) 2.008s (-33.3% 🟢) 0.757s 15 1.00x
🐘 Postgres Express 1.297s (-44.6% 🟢) 2.008s (-33.3% 🟢) 0.712s 15 1.04x
🐘 Postgres Next.js (Turbopack) 1.389s 2.009s 0.619s 15 1.11x
💻 Local Express 1.725s (-44.9% 🟢) 2.072s (-44.9% 🟢) 0.347s 15 1.38x
💻 Local Nitro 2.071s (-32.4% 🟢) 2.591s (-33.3% 🟢) 0.519s 12 1.66x
💻 Local Next.js (Turbopack) 2.083s 2.735s 0.652s 11 1.67x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 3.321s (+4.0%) 5.207s (+8.6% 🔺) 1.886s 6 1.00x
▲ Vercel Nitro 3.531s (+9.2% 🔺) 5.157s (+1.6%) 1.626s 6 1.06x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

Promise.race with 50 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 1.388s (-60.3% 🟢) 2.008s (-49.9% 🟢) 0.620s 15 1.00x
🐘 Postgres Nitro 1.391s (-60.0% 🟢) 2.009s (-49.9% 🟢) 0.618s 15 1.00x
🐘 Postgres Next.js (Turbopack) 1.771s 2.317s 0.546s 13 1.28x
💻 Local Express 4.595s (-47.8% 🟢) 5.011s (-46.0% 🟢) 0.416s 6 3.31x
💻 Local Next.js (Turbopack) 5.255s 5.513s 0.258s 6 3.79x
💻 Local Nitro 6.433s (-29.7% 🟢) 7.015s (-30.0% 🟢) 0.582s 5 4.63x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 5.399s (-15.9% 🟢) 7.246s (-11.4% 🟢) 1.847s 5 1.00x
▲ Vercel Nitro 6.645s (+30.5% 🔺) 8.837s (+29.6% 🔺) 2.193s 4 1.23x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

workflow with 10 sequential data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 0.558s (-32.0% 🟢) 1.006s (~) 0.448s 60 1.00x
🐘 Postgres Express 0.566s (-32.6% 🟢) 1.006s (-1.6%) 0.441s 60 1.01x
💻 Local Express 0.591s (-39.9% 🟢) 1.021s (-5.1% 🟢) 0.431s 59 1.06x
💻 Local Nitro 0.601s (-38.7% 🟢) 1.005s (-8.2% 🟢) 0.404s 60 1.08x
🐘 Postgres Next.js (Turbopack) 0.830s 1.024s 0.194s 59 1.49x
💻 Local Next.js (Turbopack) 0.859s 1.021s 0.163s 59 1.54x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 5.370s (-71.8% 🟢) 7.214s (-66.2% 🟢) 1.844s 9 1.00x
▲ Vercel Nitro 6.041s (-72.6% 🟢) 7.729s (-67.8% 🟢) 1.688s 8 1.13x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

workflow with 25 sequential data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 1.323s (-33.0% 🟢) 2.030s (-10.1% 🟢) 0.707s 45 1.00x
🐘 Postgres Nitro 1.390s (-27.9% 🟢) 2.030s (-3.3%) 0.640s 45 1.05x
💻 Local Express 1.480s (-50.9% 🟢) 2.005s (-44.1% 🟢) 0.526s 45 1.12x
💻 Local Nitro 1.524s (-49.8% 🟢) 2.028s (-46.0% 🟢) 0.504s 45 1.15x
🐘 Postgres Next.js (Turbopack) 1.986s 2.343s 0.357s 39 1.50x
💻 Local Next.js (Turbopack) 2.080s 2.943s 0.863s 31 1.57x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 13.722s (-60.3% 🟢) 16.049s (-56.4% 🟢) 2.327s 6 1.00x
▲ Vercel Nitro 16.784s (-57.5% 🟢) 18.494s (-55.2% 🟢) 1.710s 5 1.22x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

workflow with 50 sequential data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 2.577s (-35.4% 🟢) 3.058s (-30.0% 🟢) 0.481s 40 1.00x
🐘 Postgres Nitro 2.654s (-35.3% 🟢) 3.085s (-33.0% 🟢) 0.431s 39 1.03x
💻 Local Express 3.116s (-66.2% 🟢) 3.705s (-63.0% 🟢) 0.590s 33 1.21x
💻 Local Nitro 3.275s (-64.8% 🟢) 4.010s (-60.0% 🟢) 0.734s 30 1.27x
🐘 Postgres Next.js (Turbopack) 3.832s 4.010s 0.178s 30 1.49x
💻 Local Next.js (Turbopack) 4.301s 5.010s 0.709s 24 1.67x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 29.551s (-77.3% 🟢) 32.398s (-75.5% 🟢) 2.847s 4 1.00x
▲ Vercel Nitro 31.567s (-67.4% 🟢) 33.274s (-66.2% 🟢) 1.707s 4 1.07x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

workflow with 10 concurrent data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 0.207s (-26.8% 🟢) 1.006s (~) 0.799s 60 1.00x
🐘 Postgres Nitro 0.216s (-23.7% 🟢) 1.006s (~) 0.790s 60 1.04x
🐘 Postgres Next.js (Turbopack) 0.263s 1.007s 0.745s 60 1.27x
💻 Local Express 0.433s (-22.7% 🟢) 1.004s (~) 0.571s 60 2.10x
💻 Local Nitro 0.462s (-23.6% 🟢) 1.021s (~) 0.559s 59 2.23x
💻 Local Next.js (Turbopack) 0.580s 1.039s 0.459s 58 2.81x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 2.571s (+31.5% 🔺) 4.247s (+16.8% 🔺) 1.676s 15 1.00x
▲ Vercel Nitro 2.593s (+56.1% 🔺) 4.129s (+23.2% 🔺) 1.536s 15 1.01x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

workflow with 25 concurrent data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 0.341s (-31.4% 🟢) 1.007s (~) 0.666s 90 1.00x
🐘 Postgres Express 0.359s (-29.6% 🟢) 1.018s (+1.2%) 0.659s 89 1.05x
🐘 Postgres Next.js (Turbopack) 0.478s 1.006s 0.528s 90 1.40x
💻 Local Express 2.006s (-20.2% 🟢) 2.536s (-15.7% 🟢) 0.530s 36 5.89x
💻 Local Nitro 2.121s (-16.4% 🟢) 2.655s (-11.8% 🟢) 0.534s 34 6.23x
💻 Local Next.js (Turbopack) 2.284s 2.977s 0.693s 31 6.71x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 4.601s (+42.6% 🔺) 6.275s (+30.1% 🔺) 1.674s 15 1.00x
▲ Vercel Express 5.138s (+68.6% 🔺) 7.056s (+46.8% 🔺) 1.918s 13 1.12x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Nitro | Express

workflow with 50 concurrent data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 0.642s (-18.7% 🟢) 1.006s (~) 0.364s 120 1.00x
🐘 Postgres Express 0.647s (-21.0% 🟢) 1.006s (-1.1%) 0.359s 120 1.01x
🐘 Postgres Next.js (Turbopack) 0.958s 1.466s 0.508s 83 1.49x
💻 Local Express 9.101s (-18.7% 🟢) 9.561s (-19.9% 🟢) 0.460s 13 14.17x
💻 Local Nitro 9.763s (-12.8% 🟢) 10.361s (-11.2% 🟢) 0.598s 12 15.20x
💻 Local Next.js (Turbopack) 10.531s 11.302s 0.771s 11 16.40x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 14.507s (+95.5% 🔺) 16.514s (+78.6% 🔺) 2.008s 8 1.00x
▲ Vercel Nitro 15.750s (+103.9% 🔺) 17.409s (+85.2% 🔺) 1.659s 7 1.09x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - -

🔍 Observability: Express | Nitro

Stream Benchmarks (includes TTFB metrics)
workflow with stream

💻 Local Development

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
💻 Local 🥇 Express 1.153s (+479.2% 🔺) 2.005s (+99.6% 🔺) 0.010s (-19.0% 🟢) 2.017s (+98.1% 🔺) 0.864s 10 1.00x
🐘 Postgres Express 1.157s (+464.1% 🔺) 2.003s (+100.6% 🔺) 0.001s (-31.3% 🟢) 2.011s (+98.8% 🔺) 0.854s 10 1.00x
💻 Local Nitro 1.164s (+444.5% 🔺) 2.005s (+99.6% 🔺) 0.013s (+0.8%) 2.019s (+98.2% 🔺) 0.856s 10 1.01x
🐘 Postgres Nitro 1.166s (+468.8% 🔺) 1.999s (+100.0% 🔺) 0.001s (-33.3% 🟢) 2.010s (+98.8% 🔺) 0.844s 10 1.01x
💻 Local Next.js (Turbopack) 1.204s 2.003s 0.010s 2.018s 0.814s 10 1.04x
🐘 Postgres Next.js (Turbopack) 1.228s 2.002s 0.001s 2.011s 0.783s 10 1.06x

▲ Production (Vercel)

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 2.292s (-40.2% 🟢) 3.373s (-36.1% 🟢) 1.464s (+97.3% 🔺) 5.300s (-18.3% 🟢) 3.008s 10 1.00x
▲ Vercel Express 2.399s (-4.3%) 3.560s (-13.0% 🟢) 1.509s (+57.1% 🔺) 5.604s (~) 3.205s 10 1.05x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - - -

🔍 Observability: Nitro | Express

stream pipeline with 5 transform steps (1MB)

💻 Local Development

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 1.568s (+148.8% 🔺) 2.002s (+99.0% 🔺) 0.004s (+7.0% 🔺) 2.025s (+98.0% 🔺) 0.457s 30 1.00x
💻 Local Express 1.574s (+107.9% 🔺) 2.010s (+95.4% 🔺) 0.010s (+6.9% 🔺) 2.022s (+94.5% 🔺) 0.449s 30 1.00x
💻 Local Nitro 1.583s (+88.7% 🔺) 2.009s (+98.5% 🔺) 0.011s (+17.4% 🔺) 2.021s (+81.1% 🔺) 0.439s 30 1.01x
🐘 Postgres Nitro 1.585s (+153.9% 🔺) 2.002s (+98.9% 🔺) 0.004s (-3.3%) 2.026s (+98.1% 🔺) 0.441s 30 1.01x
💻 Local Next.js (Turbopack) 1.717s 2.008s 0.010s 2.021s 0.304s 30 1.10x
🐘 Postgres Next.js (Turbopack) 1.753s 2.010s 0.004s 2.026s 0.273s 30 1.12x

▲ Production (Vercel)

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 6.267s (-3.6%) 7.727s (-3.5%) 0.597s (+46.1% 🔺) 8.867s (~) 2.601s 7 1.00x
▲ Vercel Nitro 6.523s (-77.8% 🟢) 7.825s (-74.6% 🟢) 0.228s (+103.6% 🔺) 8.466s (-73.4% 🟢) 1.943s 8 1.04x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - - -

🔍 Observability: Express | Nitro

10 parallel streams (1MB each)

💻 Local Development

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 0.710s (-26.7% 🟢) 1.015s (-18.6% 🟢) 0.000s (+62.7% 🔺) 1.032s (-18.0% 🟢) 0.322s 59 1.00x
🐘 Postgres Express 0.714s (-25.7% 🟢) 1.028s (-19.5% 🟢) 0.000s (-20.7% 🟢) 1.048s (-19.7% 🟢) 0.335s 58 1.01x
🐘 Postgres Next.js (Turbopack) 0.816s 1.071s 0.000s 1.079s 0.263s 56 1.15x
💻 Local Express 1.361s (+11.1% 🔺) 2.014s (~) 0.000s (+20.0% 🔺) 2.016s (~) 0.655s 30 1.92x
💻 Local Nitro 1.366s (+11.7% 🔺) 2.014s (~) 0.000s (+66.7% 🔺) 2.016s (~) 0.650s 30 1.92x
💻 Local Next.js (Turbopack) 1.690s 2.013s 0.000s 2.196s 0.505s 28 2.38x

▲ Production (Vercel)

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 3.744s (+22.7% 🔺) 4.766s (+8.5% 🔺) 0.000s (-100.0% 🟢) 5.154s (+7.2% 🔺) 1.410s 12 1.00x
▲ Vercel Express 4.545s (+21.5% 🔺) 5.740s (+12.5% 🔺) 0.000s (-100.0% 🟢) 6.250s (+13.0% 🔺) 1.706s 10 1.21x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - - -

🔍 Observability: Nitro | Express

fan-out fan-in 10 streams (1MB each)

💻 Local Development

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 1.265s (-29.4% 🟢) 2.033s (-5.1% 🟢) 0.000s (-6.7% 🟢) 2.050s (-5.7% 🟢) 0.786s 30 1.00x
🐘 Postgres Express 1.315s (-25.8% 🟢) 1.996s (-8.3% 🟢) 0.000s (NaN%) 2.044s (-7.0% 🟢) 0.729s 30 1.04x
🐘 Postgres Next.js (Turbopack) 1.703s 2.299s 0.000s 2.307s 0.605s 27 1.35x
💻 Local Nitro 3.052s (-9.9% 🟢) 3.840s (-4.8%) 0.001s (+75.8% 🔺) 3.842s (-4.8%) 0.790s 16 2.41x
💻 Local Express 3.072s (-11.4% 🟢) 3.901s (-3.3%) 0.001s (+9.4% 🔺) 3.903s (-3.3%) 0.831s 16 2.43x
💻 Local Next.js (Turbopack) 3.172s 3.731s 0.001s 3.735s 0.563s 17 2.51x

▲ Production (Vercel)

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 5.571s (+36.1% 🔺) 6.817s (+26.8% 🔺) 0.000s (+63.0% 🔺) 7.240s (+25.0% 🔺) 1.670s 9 1.00x
▲ Vercel Express 5.994s (+30.7% 🔺) 7.645s (+26.9% 🔺) 0.000s (+Infinity% 🔺) 8.265s (+28.0% 🔺) 2.271s 8 1.08x
▲ Vercel Next.js (Turbopack) ⚠️ missing - - - - -

🔍 Observability: Nitro | Express

Summary

Fastest Framework by World

Winner determined by most benchmark wins

World 🥇 Fastest Framework Wins
💻 Local Express 16/21
🐘 Postgres Nitro 12/21
▲ Vercel Express 13/21
Fastest World by Framework

Winner determined by most benchmark wins

Framework 🥇 Fastest World Wins
Express 🐘 Postgres 16/21
Next.js (Turbopack) 🐘 Postgres 14/21
Nitro 🐘 Postgres 17/21
Column Definitions
  • Workflow Time: Runtime reported by workflow (completedAt - createdAt) - primary metric
  • TTFB: Time to First Byte - time from workflow start until first stream byte received (stream benchmarks only)
  • Slurp: Time from first byte to complete stream consumption (stream benchmarks only)
  • Wall Time: Total testbench time (trigger workflow + poll for result)
  • Overhead: Testbench overhead (Wall Time - Workflow Time)
  • Samples: Number of benchmark iterations run
  • vs Fastest: How much slower compared to the fastest configuration for this benchmark

Worlds:

  • 💻 Local: In-memory filesystem world (local development)
  • 🐘 Postgres: PostgreSQL database world (local development)
  • ▲ Vercel: Vercel production/preview deployment
  • 🌐 Turso: Community world (local development)
  • 🌐 MongoDB: Community world (local development)
  • 🌐 Redis: Community world (local development)
  • 🌐 Jazz: Community world (local development)
  • 🌐 Redis: Community world (local development)
  • 🌐 Redis + BullMQ: Community world (local development)
  • 🌐 Cloudflare: Community world (local development)
  • 🌐 MySQL: Community world (local development)
  • 🌐 Azure: Community world (local development)
  • 🌐 NATS JetStream: Community world (local development)
  • 🌐 Upstash: Community world (local development)

📋 View full workflow run

❌ Some benchmark jobs failed:

  • Local: success
  • Postgres: success
  • Vercel: failure

Check the workflow run for details.

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github-actions Bot commented Jun 1, 2026 •
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🧪 E2E Test Results

✅ All tests passed

Summary

Passed Failed Skipped Total
✅ ▲ Vercel Production 1266 0 219 1485
✅ 💻 Local Development 1671 0 219 1890
✅ 📦 Local Production 1671 0 219 1890
✅ 🐘 Local Postgres 1671 0 219 1890
✅ 🪟 Windows 135 0 0 135
✅ 📋 Other 769 0 176 945
Total 7183 0 1052 8235

Details by Category

✅ ▲ Vercel Production
App Passed Failed Skipped
✅ astro 109 0 26
✅ example 109 0 26
✅ express 109 0 26
✅ fastify 109 0 26
✅ hono 109 0 26
✅ nextjs-turbopack 133 0 2
✅ nextjs-webpack 133 0 2
✅ nitro 109 0 26
✅ nuxt 109 0 26
✅ sveltekit 128 0 7
✅ vite 109 0 26
✅ 💻 Local Development
App Passed Failed Skipped
✅ astro-stable 110 0 25
✅ express-stable 110 0 25
✅ fastify-stable 110 0 25
✅ hono-stable 110 0 25
✅ nextjs-turbopack-canary 116 0 19
✅ nextjs-turbopack-stable-lazy-discovery-disabled 135 0 0
✅ nextjs-turbopack-stable-lazy-discovery-enabled 135 0 0
✅ nextjs-webpack-canary 116 0 19
✅ nextjs-webpack-stable-lazy-discovery-disabled 135 0 0
✅ nextjs-webpack-stable-lazy-discovery-enabled 135 0 0
✅ nitro-stable 110 0 25
✅ nuxt-stable 110 0 25
✅ sveltekit-stable 129 0 6
✅ vite-stable 110 0 25
✅ 📦 Local Production
App Passed Failed Skipped
✅ astro-stable 110 0 25
✅ express-stable 110 0 25
✅ fastify-stable 110 0 25
✅ hono-stable 110 0 25
✅ nextjs-turbopack-canary 116 0 19
✅ nextjs-turbopack-stable-lazy-discovery-disabled 135 0 0
✅ nextjs-turbopack-stable-lazy-discovery-enabled 135 0 0
✅ nextjs-webpack-canary 116 0 19
✅ nextjs-webpack-stable-lazy-discovery-disabled 135 0 0
✅ nextjs-webpack-stable-lazy-discovery-enabled 135 0 0
✅ nitro-stable 110 0 25
✅ nuxt-stable 110 0 25
✅ sveltekit-stable 129 0 6
✅ vite-stable 110 0 25
✅ 🐘 Local Postgres
App Passed Failed Skipped
✅ astro-stable 110 0 25
✅ express-stable 110 0 25
✅ fastify-stable 110 0 25
✅ hono-stable 110 0 25
✅ nextjs-turbopack-canary 116 0 19
✅ nextjs-turbopack-stable-lazy-discovery-disabled 135 0 0
✅ nextjs-turbopack-stable-lazy-discovery-enabled 135 0 0
✅ nextjs-webpack-canary 116 0 19
✅ nextjs-webpack-stable-lazy-discovery-disabled 135 0 0
✅ nextjs-webpack-stable-lazy-discovery-enabled 135 0 0
✅ nitro-stable 110 0 25
✅ nuxt-stable 110 0 25
✅ sveltekit-stable 129 0 6
✅ vite-stable 110 0 25
✅ 🪟 Windows
App Passed Failed Skipped
✅ nextjs-turbopack 135 0 0
✅ 📋 Other
App Passed Failed Skipped
✅ e2e-local-dev-nest-stable 110 0 25
✅ e2e-local-dev-tanstack-start- 110 0 25
✅ e2e-local-postgres-nest-stable 110 0 25
✅ e2e-local-postgres-tanstack-start- 110 0 25
✅ e2e-local-prod-nest-stable 110 0 25
✅ e2e-local-prod-tanstack-start- 110 0 25
✅ e2e-vercel-prod-tanstack-start 109 0 26

📋 View full workflow run

karthikscale3
karthikscale3 approved these changes Jun 1, 2026
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Re-reviewed after the latest commits (Update trace-viewer.tsx, Update use-trace-viewer.test.ts).

Looks good to merge:

  • Pagination is correctly wired through run-detail-view → NewTraceViewer
  • Footer spinner now only shows while isLoadingMore
  • Auto-backfill cap + scroll-load via IntersectionObserver are solid
  • New pagination tests pass (8/8 locally)

Remaining follow-up is out of scope here: vercel/front parity for the new trace viewer flag path (front#72039).

@mitul-s mitul-s merged commit f0f002a into main Jun 1, 2026
279 of 304 checks passed
@mitul-s mitul-s deleted the ms/loading-spans branch June 1, 2026 19:42
@github-actions github-actions Bot mentioned this pull request Jun 1, 2026
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github-actions Bot commented Jun 1, 2026

No backport to stable for f0f002a (AI decision).

This commit fixes pagination for the new trace viewer (packages/web-shared/src/components/new-trace-viewer/ and packages/web-shared/src/components/trace-viewer-new.tsx), which does not exist on stable — verified via git ls-tree origin/stable. The accompanying change to use-trace-viewer.ts introduces a new auto-load-with-cap behavior (and tests for it) that doesn't exist on stable (stable's hook has no auto-load useEffect), so it isn't fixing a bug present there. The change builds on main-only behavior.

To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:

f0f002ae05e6b4a66eb72e1b1c48fda1bcd0f412

This was referenced Jun 1, 2026
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Open
pranaygp added a commit that referenced this pull request Jun 2, 2026
@pranaygp
Merge origin/main into ci-runtime-fast-paths
b962d47 
* origin/main:
  [world-vercel] Retry transient response-body parse failures in the HTTP client (#2204)
  Add virtualization to the trace viewer (#2205)
  Trace viewer: scroll-load events past an auto-load cap (#2200)
  fix(core): resolve forwarded stream keys across deployments (#2191)
  [e2e] Improve error labeling in event-log-race-repro CI job (#2190)
  [core] Harden event pagination response parsing (#2180) (#2179)
  Add loading skeleton to the new trace viewer (#2164)
  Add tooltip components + apply on up/down detail pane  (#2163)
  fix(swc-plugin): allow wasm host imports during link (#2174)
  [test] Forward-port reused-sleep replay divergence test (#2172)
  [e2e] Add `event-log-race-repro` label for triggering CI stress-test (#2159)
  Version Packages (beta) (#2162)
  fix(world-local): skip Nov 2025 ghost versions on npm (#2168)
  fix(core,errors): classify SDK encryption failures as RUNTIME_ERROR (#2145)
  [web-shared][web] Fix events tab search (#2107)
  Version Packages (beta) (#2147)
  Allow setting workflow attributes from steps (#2157)
  Better search handling on the trace viewer (#2144)
  [docs] Document experimental attributes feature (#2141)
@github-actions github-actions Bot mentioned this pull request Jun 2, 2026
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