Thomas Camlong
ca0bb36664
Enabled cacheComponents: true on Next 16.3.0-preview.9 and built. The flag works
and the usual migration friction is absent - zero files export dynamic,
revalidate or fetchCache.
Two blockers. The [locale] dynamic root segment needs generateStaticParams,
which is cheap: the guide is explicit that one value suffices, because
dynamicParams: true now serves the App Shell for unlisted params and upgrades in
the background. Not 53 routes x 38 locales.
Past that, 111 routes fail with the same error - SqliteError: no such table:
serverSetting. Prerendering runs at build time and the root layout
unconditionally awaits auth, two DB reads and a cookie read. For a self-hosted
app whose database is created at runtime on the user's volume there is nothing to
query during a build. Deferring those reads means moving the providers that wrap
children inside Suspense, which leaves a static shell of little more than
<html><body> - the exact failure the migration guide warns about.
And the prize is ~16-21 ms: measured TTFB is ~3 ms for a route that skips the
root layout against ~19-24 ms for one that goes through it. Meanwhile the board -
the main screen - is already dynamic(..., { ssr: false }) with a skeleton, so it
already paints an instant shell and Cache Components has no server render to
unblock there.
Recorded with both caveats: the ~20 ms is warm local SQLite and would be larger
on a network database, and the useful idea inside this - not blocking the first
byte on auth plus two DB queries - can be had by streaming those reads in the
existing layout, without the migration.
Experiment fully reverted; no code changes in this commit.
Homarr performance investigation
Measured work on Homarr's memory and rendering cost, split by subject. Every figure here comes from
a run of scripts/benchmarks/stress-restore.mts against a restored real backup — 4 boards, 51
widgets, 11 integrations, driven through an actual login — not from a synthetic or empty container.
| document | subject |
|---|---|
| SERVER-MEMORY.md | What the container's RAM is made of, and the changes that reduced it |
| CLIENT-PERFORMANCE.md | Dashboard rendering cost in Chrome: DOM, fibers, images, paint |
| WIDGET-AUDIT.md | All 50 widgets, one at a time, with a verdict and the evidence for each |
| REJECTED.md | Ideas that were implemented and measured, then abandoned — with the numbers |
| METHODOLOGY.md | The tools, and the measurement traps that produced wrong answers |
| NEXT-STEPS.md | Handoff: what is unverified, what to do next, and the set for a clean PR |
Headline result
Server RAM, merge-base 06724cfeb vs this branch, two alternated runs per side, reported as cgroup
anonymous memory because that is what counts against a container limit and cannot be reclaimed:
| stage | before | after | change |
|---|---|---|---|
| peak | 376.6 MiB | 279.3 MiB | −26% |
| boot idle | 130.5 MiB | 62.4 MiB | −52% |
| after sign-in | 247.4 MiB | 142.9 MiB | −42% |
| dashboard loaded | 293.4 MiB | 170.4 MiB | −42% |
| 4 tabs, 2 boards | 366.5 MiB | 258.2 MiB | −30% |
| after 2 min idle soak | 323.7 MiB | 200.8 MiB | −38% |
No before/after range overlaps at any stage. The cost is +18% CPU (solid, non-overlapping).
The changes that did it, by ratio
| change | size | effect |
|---|---|---|
--max-semi-space-size=4 |
1 line | −19% idle, −21% peak |
preloadEntriesOnStart: false |
1 line | −52% anon at idle, 310 fewer files even at full load |
| Umami: stop fetching 100k raw events per refresh | 1 file | −26% peak, −93% transient buffers |
serverExternalPackages (mysql2/pg + 8 more) |
1 block | −21 MiB idle |
| ssh2's 16 MiB WASM heap (docker-modem patch) | 1 patch | −15 to −18 MiB external |
content-visibility on media-release cards |
4 lines | −59% image requests, −41% layout objects |
What is left, and why it is hard
One lever has real headroom and it pays twice. Roughly 41 MiB of retained bundle source and ~38 MiB of V8 compiler zone memory both scale with how much JavaScript the server loads and compiles, and the largest single contributor is a 16.10 MiB subtree reached by every API route — the tRPC router importing every integration eagerly. Reducing that reduces both.
Everything else has been measured and closed: see REJECTED.md.