Cache runtime data for partially static pages on initial load (resume) by unstubbable · Pull Request #90888 · vercel/next.js

unstubbable · 2026-03-04T20:31:07Z

When a partially static page with unstable_instant: { prefetch: 'runtime' } is loaded as initial HTML (PPR resume), the server now spawns a runtime prerender after the resume render fills the caches, embedding the result as the p field on the InitialRSCPayload. The client extracts this stream during hydration via
processRuntimePrefetchStream and writes the data into the segment cache.

This mirrors the existing navigation path where
generateStagedDynamicFlightRenderResult embeds the runtime prefetch stream in the NavigationFlightResponse. Both paths reuse the same spawnRuntimePrefetchWithFilledCaches function (renamed from spawnRuntimePrefetchDuringNavigation since it is no longer specific to navigations).

When a partially static page with `unstable_instant: { prefetch: 'runtime' }` is loaded as initial HTML (PPR resume), the server now spawns a runtime prerender after the resume render fills the caches, embedding the result as the `p` field on the `InitialRSCPayload`. The client extracts this stream during hydration via `processRuntimePrefetchStream` and writes the data into the segment cache. This mirrors the existing navigation path where `generateStagedDynamicFlightRenderResult` embeds the runtime prefetch stream in the `NavigationFlightResponse`. Both paths reuse the same `spawnRuntimePrefetchWithFilledCaches` function (renamed from `spawnRuntimePrefetchDuringNavigation` since it is no longer specific to navigations).

nextjs-bot · 2026-03-06T10:00:17Z

Stats from current PR

🔴 1 regression

Metric	Canary	PR	Change	Trend
node_modules Size	477 MB	477 MB	🔴 +100 kB (+0%)	██▁▁▁

📊 All Metrics

📖 Metrics Glossary

Dev Server Metrics:

Listen = TCP port starts accepting connections
First Request = HTTP server returns successful response
Cold = Fresh build (no cache)
Warm = With cached build artifacts

Build Metrics:

Fresh = Clean build (no .next directory)
Cached = With existing .next directory

Change Thresholds:

Time: Changes < 50ms AND < 10%, OR < 2% are insignificant
Size: Changes < 1KB AND < 1% are insignificant
All other changes are flagged to catch regressions

⚡ Dev Server

Metric	Canary	PR	Change	Trend
Cold (Listen)	559ms	560ms	✓	▅█▁▁▁
Cold (Ready in log)	558ms	556ms	✓	▄█▁▁▁
Cold (First Request)	1.199s	1.233s	✓	▃█▁▁▁
Warm (Listen)	560ms	560ms	✓	▅█▁▁▁
Warm (Ready in log)	552ms	553ms	✓	▃█▁▁▁
Warm (First Request)	454ms	455ms	✓	▃█▁▁▁

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	456ms	456ms	✓	█▁▁▁▁
Cold (Ready in log)	451ms	453ms	✓	█▁▄▆▅
Cold (First Request)	2.062s	2.062s	✓	█▁▃▄▃
Warm (Listen)	456ms	456ms	✓	█▁▁▁▁
Warm (Ready in log)	453ms	453ms	✓	█▁▅▄▃
Warm (First Request)	2.062s	2.000s	✓	█▁▃▃▃

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	5.169s	5.154s	✓	▃█▁▁▁
Cached Build	5.092s	5.127s	✓	▃█▁▁▁

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	14.474s	14.550s	✓	█▁▁▁▁
Cached Build	14.564s	14.628s	✓	█▁▁▁▁
node_modules Size	477 MB	477 MB	🔴 +100 kB (+0%)	██▁▁▁

📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **402 kB** → **402 kB** ⚠️ +155 B

80 files with content-based hashes (individual files not comparable between builds)

Server

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	766 B	767 B	✓
Total	766 B	767 B	⚠️ +1 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	446 B	450 B	✓
Total	446 B	450 B	⚠️ +4 B

📦 Webpack

Client

Main Bundles

	Canary	PR	Change
5528-HASH.js gzip	5.54 kB	N/A	-
6280-HASH.js gzip	59.4 kB	N/A	-
6335.HASH.js gzip	169 B	N/A	-
912-HASH.js gzip	4.59 kB	N/A	-
e8aec2e4-HASH.js gzip	62.6 kB	N/A	-
framework-HASH.js gzip	59.7 kB	59.7 kB	✓
main-app-HASH.js gzip	256 B	253 B	🟢 3 B (-1%)
main-HASH.js gzip	39.1 kB	39.1 kB	✓
webpack-HASH.js gzip	1.68 kB	1.68 kB	✓
262-HASH.js gzip	N/A	4.59 kB	-
2889.HASH.js gzip	N/A	169 B	-
5602-HASH.js gzip	N/A	5.55 kB	-
6948ada0-HASH.js gzip	N/A	62.6 kB	-
9544-HASH.js gzip	N/A	60.3 kB	-
Total	233 kB	234 kB	⚠️ +817 B

Polyfills

	Canary	PR	Change
polyfills-HASH.js gzip	39.4 kB	39.4 kB	✓
Total	39.4 kB	39.4 kB	✓

Pages

	Canary	PR	Change
_app-HASH.js gzip	194 B	194 B	✓
_error-HASH.js gzip	183 B	180 B	🟢 3 B (-2%)
css-HASH.js gzip	331 B	330 B	✓
dynamic-HASH.js gzip	1.81 kB	1.81 kB	✓
edge-ssr-HASH.js gzip	256 B	256 B	✓
head-HASH.js gzip	351 B	352 B	✓
hooks-HASH.js gzip	384 B	383 B	✓
image-HASH.js gzip	580 B	581 B	✓
index-HASH.js gzip	260 B	260 B	✓
link-HASH.js gzip	2.51 kB	2.51 kB	✓
routerDirect..HASH.js gzip	320 B	319 B	✓
script-HASH.js gzip	386 B	386 B	✓
withRouter-HASH.js gzip	315 B	315 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Total	7.98 kB	7.98 kB	✅ -1 B

Server

Edge SSR

	Canary	PR	Change
edge-ssr.js gzip	125 kB	125 kB	✓
page.js gzip	256 kB	257 kB	✓
Total	380 kB	382 kB	⚠️ +1.28 kB

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	617 B	615 B	✓
middleware-r..fest.js gzip	156 B	155 B	✓
middleware.js gzip	43.8 kB	43.7 kB	✓
edge-runtime..pack.js gzip	842 B	842 B	✓
Total	45.4 kB	45.3 kB	✅ -122 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	715 B	718 B	✓
Total	715 B	718 B	⚠️ +3 B

Build Cache

	Canary	PR	Change
0.pack gzip	4.06 MB	4.08 MB	🔴 +16 kB (+0%)
index.pack gzip	104 kB	103 kB	✓
index.pack.old gzip	104 kB	103 kB	🟢 1.1 kB (-1%)
Total	4.27 MB	4.28 MB	⚠️ +14.3 kB

🔄 Shared (bundler-independent)

Runtimes

	Canary	PR	Change
app-page-exp...dev.js gzip	322 kB	322 kB	✓
app-page-exp..prod.js gzip	171 kB	171 kB	✓
app-page-tur...dev.js gzip	322 kB	322 kB	✓
app-page-tur..prod.js gzip	171 kB	171 kB	✓
app-page-tur...dev.js gzip	318 kB	319 kB	✓
app-page-tur..prod.js gzip	169 kB	169 kB	✓
app-page.run...dev.js gzip	319 kB	319 kB	✓
app-page.run..prod.js gzip	169 kB	169 kB	✓
app-route-ex...dev.js gzip	70.9 kB	70.9 kB	✓
app-route-ex..prod.js gzip	49.3 kB	49.3 kB	✓
app-route-tu...dev.js gzip	70.9 kB	70.9 kB	✓
app-route-tu..prod.js gzip	49.3 kB	49.3 kB	✓
app-route-tu...dev.js gzip	70.5 kB	70.5 kB	✓
app-route-tu..prod.js gzip	49 kB	49 kB	✓
app-route.ru...dev.js gzip	70.4 kB	70.4 kB	✓
app-route.ru..prod.js gzip	49 kB	49 kB	✓
dist_client_...dev.js gzip	324 B	324 B	✓
dist_client_...dev.js gzip	326 B	326 B	✓
dist_client_...dev.js gzip	318 B	318 B	✓
dist_client_...dev.js gzip	317 B	317 B	✓
pages-api-tu...dev.js gzip	43.2 kB	43.2 kB	✓
pages-api-tu..prod.js gzip	32.9 kB	32.9 kB	✓
pages-api.ru...dev.js gzip	43.2 kB	43.2 kB	✓
pages-api.ru..prod.js gzip	32.9 kB	32.9 kB	✓
pages-turbo....dev.js gzip	52.6 kB	52.6 kB	✓
pages-turbo...prod.js gzip	38.5 kB	38.5 kB	✓
pages.runtim...dev.js gzip	52.6 kB	52.6 kB	✓
pages.runtim..prod.js gzip	38.5 kB	38.5 kB	✓
server.runti..prod.js gzip	62 kB	62 kB	✓
Total	2.84 MB	2.84 MB	⚠️ +1.3 kB

📝 Changed Files (8 files)

Files with changes:

app-page-exp..ntime.dev.js
app-page-exp..time.prod.js
app-page-tur..ntime.dev.js
app-page-tur..time.prod.js
app-page-tur..ntime.dev.js
app-page-tur..time.prod.js
app-page.runtime.dev.js
app-page.runtime.prod.js

View diffs

app-page-exp..ntime.dev.js

failed to diff

app-page-exp..time.prod.js

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app-page-tur..ntime.dev.js

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app-page-tur..time.prod.js

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app-page-tur..ntime.dev.js

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app-page-tur..time.prod.js

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app-page.runtime.dev.js

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app-page.runtime.prod.js

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📎 Tarball URL

https://vercel-packages.vercel.app/next/commits/fc11844506e24959fbc88df2a5029510ab4a8e0e/next

#90888) When a partially static page with `unstable_instant: { prefetch: 'runtime' }` is loaded as initial HTML (PPR resume), the server now spawns a runtime prerender after the resume render fills the caches, embedding the result as the `p` field on the `InitialRSCPayload`. The client extracts this stream during hydration via `processRuntimePrefetchStream` and writes the data into the segment cache. This mirrors the existing navigation path where `generateStagedDynamicFlightRenderResult` embeds the runtime prefetch stream in the `NavigationFlightResponse`. Both paths reuse the same `spawnRuntimePrefetchWithFilledCaches` function (renamed from `spawnRuntimePrefetchDuringNavigation` since it is no longer specific to navigations).

nextjs-bot added created-by: Next.js team PRs by the Next.js team. tests type: next labels Mar 4, 2026

unstubbable marked this pull request as ready for review March 4, 2026 21:16

unstubbable requested a review from acdlite March 5, 2026 11:23

unstubbable force-pushed the hl/cached-navs-5 branch from 84c7d21 to fc11844 Compare March 6, 2026 09:41

acdlite approved these changes Mar 6, 2026

View reviewed changes

unstubbable merged commit 0268c7b into canary Mar 6, 2026
284 of 286 checks passed

unstubbable deleted the hl/cached-navs-5 branch March 6, 2026 16:46

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Cache runtime data for partially static pages on initial load (resume)#90888

Cache runtime data for partially static pages on initial load (resume)#90888
unstubbable merged 1 commit intocanaryfrom
hl/cached-navs-5

unstubbable commented Mar 4, 2026

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nextjs-bot commented Mar 6, 2026

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unstubbable commented Mar 4, 2026

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nextjs-bot commented Mar 6, 2026

Stats from current PR

🔴 1 regression

⚡ Dev Server

📦 Dev Server (Webpack)

⚡ Production Builds

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🔄 Shared (bundler-independent)

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