Oxicloud/benches/ROUND11.md

Round 11 — StoragePath re-representation, classifier fusion, memoized static bodies, query-shape pack, SPA fine-grained stars

Benchmark-gated, same rule as ROUND2-10: every change ships with a BEFORE/AFTER benchmark and an equivalence/safety gate; an AFTER that doesn't beat its BEFORE gets rolled back or redesigned. Three candidates went through exactly that loop this round (§Rejected): the moka and_upsert_with rate-limiter rewrite measured SLOWER than the two-op shape it was meant to replace and was redesigned as a lock-free get+insert; the GET/HEAD Last-Modified stack-render port measured neutral-to-worse (the chrono String is already the terminal allocation) and was dropped; the first search-page drain(range) model lost to to_vec on wall and was reshaped as into_iter().skip().take().

Measured on 4 cores / 15 GiB, local PostgreSQL 16 (fsync off), release profile; frontend on Node 22 / vitest 4 (jsdom). Reproduce any row with the command in its section.

Summary

(numbers filled from the final runs below)

#	change	key metric	before → after
1	REST download: dead FileDto clone → capture mime/size + move	allocs per download	7 → 0 (dead clone removed)
2	StoragePath → single canonical joined String (segments derived lazily; entity path_string duplicate field removed)	allocs / wall per 500-row page	TBD
3	Display classifier fusion (classify_display, stack-lowered ext shared by the three trees)	ns / allocs per listing row	TBD
4	/status.php → OnceLock<Bytes>	ns / allocs per poll	TBD
5	/openapi.json → OnceLock<Bytes> (was: rebuild 171 KiB spec per request)	ns per request	TBD
6	NC upload-session PROPFIND: write! + capacity + stack dates	ns / allocs per 256-chunk PROPFIND	TBD
7	CSRF header token borrow compare	ns / allocs per state-changing request	TBD
8	Thumbnail/preview ETag: as_str push (Debug-identical bytes)	ns per thumbnail request	TBD
9	Recent-handler id: stack encode_lower	ns / allocs per call	TBD
10	4xx body: borrowed serialize + ErrorKind::as_str + not_found clone kill	ns / allocs per 404	TBD
11	vCard emit: write! (+ borrowed address fields)	ns / allocs per vCard	TBD
12	Search page: into_iter().skip().take() move	allocs per 50-item page	TBD
13	Content-hit verify: parse-once pairs	ns per 100-hit page	TBD
14	Group last-user check: HashSet probe	ns per 500×500 check	TBD
15	Retry op-label: lazy closure	ns / allocs per blob op	TBD
16	encrypt_bytes: in-place detached (write side now mirrors the in-place read)	ns / allocs per 256 KiB chunk	TBD
17	Encrypted collect_stream: chunk-sized reserve	allocs per 1 MiB read	TBD
18	Recluster cosine: precomputed norms (bit-identical)	ns per 200-face pass	TBD
19	CalendarEventDto: into_parts move (11 KiB ical_data copy gone)	ns / allocs per event	TBD
20	RateLimiter: lock-free get + insert	ns / allocs per limited request	TBD
Q1	Deferred upload registration: 3 round-trips → 1 CTE insert	ms per uploaded file	TBD
Q2	Calendar/AddressBook/Playlist authz direct_grant_cache	ms per DAV check	TBD
Q3	expand_user: tokio::join! the 2 independent queries	ms per cold expansion	TBD
Q4	Geo clusters: min(file_id)::text (cast per cluster, not per row)	ms per viewport	TBD
Q5	Recluster persistence: per-face UPDATEs → one UNNEST batch	ms per 200-face apply	TBD
L1	Log writer: tracing-appender non_blocking (lossy=false)	p99 emit µs under contention	TBD
S1	SPA ResourceList.selectedEntries: O(N)×2 per toggle → O(k·log k), hosts consume the snippet param	comparisons per toggle	2N → k
S2	SPA Recent: star reads favoriteIds prop, mapper no longer set-dependent	rows re-mapped per star click	N → 0
S3	SPA admin timeAgo: cached Intl.DateTimeFormat	constructions per 1000 formats	≤1 (was 1000)

Also shipped without a dedicated row: already_exists clone kill (same shape as not_found), CardDAV getlastmodified stack render (per-contact REPORT path, ROUND10-§13 helper + fallback), NC capabilities poll logs demoted to debug (INFO forced a locked-stdout write per client poll), trash to_dto into_parts move + interned display fields (trash listing

• path-resolver rows now share the ROUND9 interning).

Rejected / reworked this round (the discipline working)

• RateLimiter entry().and_upsert_with: 1 846.5 → 1 862.1 ns and 8.0 → 9.1 allocs/op — moka's compute-entry machinery costs more than the two-op shape it replaced. Redesigned as lock-free get (borrows the key, no alloc) + insert; identical counter sequence gated.
• GET/HEAD Last-Modified stack-render port: chrono's to_rfc2822() String IS the terminal allocation the header needs (44.3 ns incl. the alloc vs 46.5 ns for stack render + the same alloc). Only body-emit sites (where write! lands in an existing buffer) benefit — those were ported (§6, CardDAV); the header sites were left on chrono.
• Search page drain(range).collect(): −300 allocs but slower on wall than to_vec in the first model (tail memmove). Reshaped as into_iter().skip().take().collect() — moves the page, drops the rest, no tail shift.

Deferred / flagged (not shipped this round)

• NC preview 304 still runs get_file (preview_handler.rs): the object-id → file fetch on the revalidation path is only needed for existence semantics (a deleted file must 404, not 304). Dropping it is a behavior decision — same class as the standing CalDAV authz-before-fetch reorder — flagged for maintainer sign-off.
• CachedBlobBackend's Mutex<LruCache> index serializes every cached read; a moka byte-weigher migration (the file-content-cache pattern) is the natural fix but touches eviction-unlink semantics — deserves its own round with a concurrency bench.
• Capture-metadata extraction reads each media file 2-3× (media_metadata_service.rs: kamadak full read + nom-exif path re-read
  • track fallback re-read). Feeding nom-exif from the in-memory buffer needs its MediaSource API verified on the pinned version.
• CachedBlobBackend::local_blob_path sync stat (ROUND10 flag stands): needs an async port variant.
• Azure SDK 0.21 stack drags duplicate dependency trees (h2 0.3+0.4, two hashbrown generations, base64 0.13) into the binary; an SDK bump is a dedicated migration, not a perf tweak.
• AudioMetadataRepository::list_by_{artist,album,genre} are dead code (never called) with seq-scan ILIKE shapes — flag for deletion rather than indexing.
• CachedBlobBackend::put_blob cache population silently fails for S3/Azure whole-file puts (the inner backend deletes the source before the cache copy runs) — correctness note for maintainers, not perf.
• CalDAV authz-before-fetch reorder — ROUND9/10 flag stands.

Environment / methodology

• cargo run --release --features bench --example bench_round11_micro (pure CPU, counting allocator, BEFORE replicas vs shipped code).
• cargo run --release --features bench --example bench_round11_queries (Postgres; seeds + sweeps its own fixtures).
• BENCH_LOG_ARM=sync|nonblocking [BENCH_LOG_WRITER=slow] cargo run --release --features bench --example bench_log_writer >/dev/null.
• cd frontend && npx vitest run src/lib/components/round11.bench.test.ts.
• Regression guards from earlier rounds re-run after the StoragePath / classifier changes: bench_row_path (round-4 gates) and bench_dto_map (round-3 gates).