Round 3 of benchmark-gated optimizations (benches/ROUND3.md; every change
gated by a before/after benchmark — an AFTER that did not beat its BEFORE
was to be rolled back; none needed it. Equivalence gates assert identical
row sequences / byte-identical output on every behavior-preserving rewrite):
DB hot paths (local PG16, EXPLAIN-verified):
- Web-UI listing (list_resources_paged): cursor pushed INSIDE the
folders/files UNION-ALL branches as sargable row-value comparisons with
per-branch ORDER/LIMIT + two partial expression indexes
(folder_id, LOWER(name), id). 20k-entry folder: 26.6 -> 1.3 ms/page
(19.5x); other sort modes at parity or better. New migration
20260918000000. [benches/LISTING-KEYSET.md section in ROUND3]
- Photos timeline (list_media_files): per-drive CROSS JOIN LATERAL top-N
on the timeline index, joins moved above the top-N. 50k-photo library:
97.4 -> 1.6 ms/page (55.7x). The old "LIMIT stops the scan early"
comment was refuted by EXPLAIN.
- PROPFIND sub-folders (both DAV surfaces): keyset list_folders_batch off
idx_folders_unique_name replaces COUNT(*) OVER() + LIMIT/OFFSET
(5k dirs: 79.7 -> 17.9 ms full walk, 4.5x).
Concurrency:
- Basic-auth cache single-flight (moka try_get_with): 8 concurrent DAV
connections at TTL expiry paid 8 Argon2id runs (2.6 s CPU + 8x64 MiB);
now 1 (300 ms). Failed verifications remain uncached.
- CachedBlobBackend per-hash single-flight + unique tmp names: 16
concurrent cold readers = 16 full remote downloads racing truncating
writes on ONE deterministic .tmp (corruptible cache); now 1 download
(16x less egress, 2.8x wall on a shared link) and torn files can never
be renamed into the cache.
I/O and allocations:
- Chunk-assembly reads 64K -> 512K buffers (2.3x, 8x fewer syscalls);
chunk-spool writes via BufWriter 512K (5.6x, 32x fewer syscalls).
- S3/Azure put_blob_from_bytes_unsynced overrides: dedup settle no longer
pays a HEAD probe per new chunk (2 RTT -> 1, 1.8x); Azure stops copying
every chunk (Bytes -> Body, -0.44 ms - 4 MiB alloc per 4 MiB chunk).
- Entity->DTO mapping: Arc<str> interning of closed-set display fields +
common MIMEs, 1-alloc etag/size formatting, FolderDto moves instead of
clones. File row: 11 -> 4 allocs; folder row: 11.8 -> 1 (2.1x faster).
- CardDAV REPORT: deleted dead per-contact vCard pre-generation and the
O(N^2) uid scan whose result was discarded (5k contacts: 55.7 -> 5.7 ms,
9.8x); byte-identical XML asserted.
- Search-results cache: byte weigher + 32 MiB budget
(OXICLOUD_SEARCH_CACHE_MAX_BYTES) replaces the 1000-ENTRY cap that let
~300 MiB of enriched rows sit in RSS; read latency parity.
- Dropped aws-config + aws-smithy-types (zero references; -82 dep-graph
nodes, three SDK stacks gone from every build). tokio "process" is now
an explicit feature (was enabled transitively by aws-config).
Frontend:
- Cached Intl.DateTimeFormat keyed by (locale, options) in formatDate and
4 sibling callsites: 20k dates 2612 -> 51 ms (51.6x); vitest gate
asserts output identity across locales and a 3x floor.
Validation: cargo fmt + clippy --all-features --all-targets -D warnings
clean; 518 unit + 548 integration-cfg tests green; new-shape endpoints
smoke-tested end-to-end over HTTP (all 5 listing sort modes with cursor
walks, WebDAV PROPFIND Depth-1, photos timeline, Basic-auth DAV login);
frontend npm run check clean, new vitest gates green.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EBsU2qEzny3A8WQUEuMNCr
Round 2 of benchmark-gated optimizations (benches/ROUND2.md; every change
gated by a before/after in examples/bench_round2.rs — an AFTER that did
not beat its BEFORE was to be rolled back; none needed it):
- Range requests (REST/DAV/shares) answered from the moka content cache
for sub-10MB files: PG resolve + open/seek/read -> Bytes::slice.
256KiB seeks: 1,730/s -> 3.7M/s (p50 552us -> 0.15us).
- Streaming folder/share ZIPs via tokio duplex: TTFB no longer scales
with archive size (326ms -> 0.4ms on 192MiB corpus; total also faster).
Content-Length dropped (size unknown up front).
- NC chunked-upload per-PUT gate: O(k) directory scan+stat -> in-RAM
per-session counter (lazy rebuild on cold start). 1,000-chunk upload
gate cost: 33.1s -> 0.09s cumulative.
- Delta download + commit-verify now use the CDC path's
buffered(read_prefetch) read-ahead: 64-chunk drain at 5ms open
latency 440ms -> 51ms; order preserved.
- CDC ingest settles batches on a spawned task (depth-1 pipeline) so
the source stream keeps flowing during PG pin + backend writes;
rollback ledger shared + lock-serialized so compensation stays exact
on cancellation. 512MiB paced ingest: 60-69 -> 74-75 MB/s.
OXICLOUD_INGEST_OVERLAP=0 restores inline settling (ops/bench hatch).
- Frontend: instant-upload BLAKE3 hashing moved off the main thread to
a bounded Web Worker pool (File handles by reference); vitest gate
asserts the pool beats sequential (first gate draft posting buffers
was 2.6x slower and was rewritten — copies dominated).
Validation: cargo fmt + clippy -D warnings clean; 514 unit + 544
integration tests green; 270 frontend tests green.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CBK1RdtzyP6759Muqe1K1w
Every change is benchmark-verified (harness + before/after numbers in
benches/, measured on this branch; reproduction commands in each doc):
DAV / sync-client hot paths
- PROPFIND dead-properties: one = ANY($1) query per 500-child page instead
of one sequential query per child, and indexable `=` predicates instead
of IS NOT DISTINCT FROM (seq scans). 2,000-child folder: 1.07-4.54 s of
DB chatter -> 4-6 ms (258-773x). Applied to native + NC PROPFIND and
both NC REPORT handlers. [benches/DEAD-PROPS.md]
- Folder paging: keyset cursor (name > $last) + new partial index
(folder_id, name) replaces LIMIT/OFFSET full-folder rescan per page.
Full 20k-file walk: 1266 ms -> 77 ms (16.5x). New migration
20260917000000. [benches/PROPFIND-PAGING.md]
- NC chroot / default-drive resolution: moka caches (30 s TTL, explicit
invalidation on drive mutations) for find_default_for_user and the
markerless chroot FolderDto. 2 uncached queries + 2 pool checkouts per
NC/WebDAV/WOPI request -> sub-us moka hit (p50 0.7-3.6 ms -> ~1 us).
[benches/CHROOT-CACHE.md]
- Quota: PROPFINDs whose prop list never names a quota prop skip the
2-query resolution entirely (wants_quota()); the remaining lookups read
2 columns instead of the full auth.users row with its <=512 KiB avatar
(11-16x, p50 3.4 ms -> 0.29 ms). Same narrow read now gates every
upload quota check. [benches/QUOTA-PATH.md]
CPU on the request path
- ZIP exports (folder download, share ZIP, batch download): entries whose
MIME says already-compressed (JPEG/MP4/zip/pdf/...) are Stored instead
of Deflate - deflate ran inline on the tokio writer task at ~41 MB/s
for ~0% size gain. Mixed media corpus: 4.31x wall and CPU, archive size
unchanged. Shared predicate in common::mime_detect. [benches/ZIP-MEDIA.md]
- Compression layers: tower-http's default maps to Brotli QUALITY 11
(verified in brotli-8.0.2 source and empirically: 90 ms per 64 KiB JSON
response, 1.3 s per 700 KiB bundle). Both layers pinned to Precise(4):
99x less CPU for ~15% more bytes. SPA assets are now precompressed at
build time (scripts/precompress.mjs, 77% smaller) and served via
ServeDir::precompressed_br/gzip: 2016x less per-request work, and
clients get the better q11 bytes. [benches/STATIC-PRECOMPRESSED.md]
Batched / cached backend paths [benches/NPLUS1-AND-CACHES.md]
- Content-search ReBAC re-verification: new
AuthorizationEngine::check_files_read_batch (default = old loop;
PgAclEngine override batches drive resolution + reuses role cache).
200 sequential point SELECTs per search -> 1-2 queries.
- Batch-ZIP subtree downloads: drop per-file re-authz + per-file Recent
recording (2 writes/file) for subtree entries already authorized at the
root - mirrors the native folder-download path. ~6,000 statements
removed from a 2,000-file archive.
- CDC chunk manifests: immutable by content address, now moka-cached
(weight-bounded 32 MiB, 60 s TTL, positive-only, invalidated on delete)
- removes one manifest query (p50 0.44-4.4 ms) from every stream,
range and full blob read.
- People tab: grouped COUNT + batched cover lookup instead of dragging
every face row with its 2 KiB embedding (10k faces: 30.4 ms & 21 MB ->
3.8 ms & 1.3 KB, 8.1x); merge() is one set-based UPDATE.
[benches/PEOPLE-LIST.md]
- Photos timeline cursor: raw timestamptz comparison instead of
EXTRACT(EPOCH ...) wrapper + IS NULL OR disjunction - cursor is an
index boundary again, deep scroll stops re-scanning skipped rows.
- Public share landing: one atomic UPDATE ... access_count + 1 (was
SELECT + full-row write-back: racy, lost updates, clobbered concurrent
owner edits) - 3 round-trips -> 2 per visit.
- move_to_trash: dead full-entity SELECT feeding a documented no-op
removed from both branches; dead fields dropped from TrashService.
- NFC normalization: is_nfc_quick fast path skips the decompose/recompose
state machine for the ~100% already-NFC case (every row loaded from PG).
Frontend
- Large folders paint after page one (~200 items) via fetchFolderListing's
new onPage hook instead of waiting for every sequential page.
- Tested-and-reverted (kept for the record): cached Intl.Collator for name
sorts - vitest showed it 2x SLOWER than V8's argument-less localeCompare
fast path (5.6 ms vs 12.1 ms / 5k names). Sort order untouched.
New bench harnesses under examples/ (bench feature): zip_media,
dead_props, chroot_cache, quota_path, people_list, propfind_paging,
static_precompress.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CBK1RdtzyP6759Muqe1K1w
This reverts ee51b32. The create_new change showed no measurable throughput
benefit — three 9-rep interleaved runs on the same ext4 device swung −12%..+21%
at the 256 KiB CDC size (a negative stat on a warm dentry cache is ~µs, below
the shared-disk noise floor). Applying the same "no change without a measured
win" bar used for the pool-sizing revert: the idiom/TOCTOU angle is real but the
race is already prevented upstream by the PG pin-or-classify serialisation, so
it's defence-in-depth only — not enough to keep an unmeasured change. Reverts
the production change, the bench, and its doc together.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JG5yYZ9s868mJwqT2Qz7ez
Replace the try_exists(stat) + File::create(O_CREAT|O_TRUNC) pair with a single
OpenOptions::create_new (O_CREAT|O_EXCL), treating AlreadyExists as the existing
idempotent skip. One metadata syscall per new chunk instead of two (each a
spawn_blocking round-trip), and O_EXCL closes the check-then-create TOCTOU the
old pair left open (a racing writer could be truncated).
Honest measurement caveat (benches/BLOB-WRITE.md): the wall-clock throughput
effect is BELOW the noise floor of the test environment — three 9-rep
interleaved runs on the same ext4 device swing −12%..+21% at the 256 KiB CDC
size, because a negative stat on a warm dentry cache is ~µs, dwarfed by the
chunk's create+write+flush. So this is justified as a code-quality / correctness
change (canonical idiom, strictly fewer syscalls, closes a TOCTOU, zero
downside), NOT as a benchmarked perf win.
The sibling idea — reusing the File handle for the fsync sweep — is deliberately
NOT done: sync_blobs is a single end-of-stream sweep over all the upload's new
hashes, so retaining handles would hold thousands of FDs open (>ulimit) on a
large upload. The re-open sweep is a deliberate FD-frugal design.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JG5yYZ9s868mJwqT2Qz7ez
This reverts the image-pool migration (commit 5629ba6). The bench
(bench_pool_concurrency / POOL-CONCURRENCY.md) measured the one pool it could
isolate — the thumbnail decode semaphore — and found flat throughput, p99 AND
peak RSS (137 MiB) from K=1..16: shrink-on-load already makes each decode
RAM-cheap, so sizing it to the CFS quota gains nothing measurable. Adding code
without a measured benefit isn't worth it.
Kept: the effective_parallelism() helper (it has a *measured* win in the Tokio
runtime — benches/RUNTIME.md) and the benchmark itself (reusable). The ffmpeg
video fan-out has a plausible a-priori case (one OS process per permit) but is
left as a future, deliberately-measured change rather than shipped on
speculation. Doc updated to record the decision.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JG5yYZ9s868mJwqT2Qz7ez
Adds Part B (peak RSS for K concurrent decodes) to bench_pool_concurrency and
records the findings in benches/POOL-CONCURRENCY.md.
Honest result: under a 2-core quota the thumbnail decode pool shows flat
throughput, p99, AND peak RSS (137 MiB) from K=1..16 — shrink-on-load already
made each decode RAM-cheap, so over-permitting costs nothing measurable here.
The effective_parallelism() migration is therefore a correctness/consistency
change with no downside, mainly protecting the transcode + ffmpeg pools (and
extreme host-core/quota ratios) this box can't reproduce — not a throughput win.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JG5yYZ9s868mJwqT2Qz7ez
Companion benches/*.md (matching the repo convention) capturing the
before/after numbers and the honest interpretation behind the read_prefetch
1->2 tuning and the runtime pool sizing.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JG5yYZ9s868mJwqT2Qz7ez
GET /api/photos sent only X-Next-Cursor — no ETag — so every gallery
re-mount rebuilt up to 500 PhotoDtos, serde-serialized the whole vector,
and shipped the full body even when nothing changed.
The handler now emits a lightweight content-derived ETag
(hash of before + limit + max(modified_at) + row count) and honours
If-None-Match, with Cache-Control: private, no-cache so the SPA's default
fetch cache mode always revalidates. An unchanged "navigate away and back"
becomes an empty 304 instead of a full rebuild + reserialize + transfer.
The DB query still runs (the cheap part); the win is skipping the DTO
build, serialization, and body bytes.
Proven end-to-end (throwaway Postgres + server, 7 images):
1st GET (no If-None-Match) -> 200 4586 bytes + ETag
2nd GET (If-None-Match matches) -> 304 0 bytes
3rd GET (If-None-Match stale) -> 200 4586 bytes (correctly invalidated)
~655 B/photo, so a full 500-row first page saves ~320 KB + a 500-DTO
build/serialize per unchanged revalidation. Unlike a cold load this is the
common gallery-navigation path, so it hits real user-facing latency.
Regression test: tests/api/photos_etag.hurl (added to the api-test suite).
Methodology in benches/PHOTOS-ETAG.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
read_blob_bytes read the same storage.chunk_manifests PK row twice per
full-blob read — blob_size (SELECT total_size) then read_blob_stream
(SELECT chunk_hashes) — even though both columns live in one row. Fold
them into a single `SELECT chunk_hashes, total_size` and share the chunk
stream builder via a new stream_chunks helper. The legacy (no-manifest)
path is unchanged. Output is identical; the read just costs one fewer DB
round-trip.
Benchmark (examples/bench_blob_manifest.rs, isolates the manifest lookup
against the real Postgres): ~1.9x throughput and p50/p99 roughly halved on
that sub-step; the win is the removed round-trip under pool pressure during
upload bursts. Note this is the manifest sub-step only — end-to-end
read_blob_bytes is dominated by the actual chunk reads, and it is a
background path (thumbnail generation / EXIF / indexing), not normal gallery
serving. Methodology + honest framing in benches/BLOB-MANIFEST.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Videos now get a thumbnail generated eagerly server-side on upload, through
the same WebP/blob-hash pipeline as photos — instead of the old browser path
that only ran when the Photos grid first rendered a video tile, re-downloaded
the whole video to seek a frame, and PUT 3 JPEGs back (and produced nothing at
all for HEVC/.mov, which a browser <video> cannot decode).
- New VideoFramePort (application) + FfmpegVideoFrameService / NoopVideoFrameService
(infrastructure): shell out to the system ffmpeg (no compile-time libav dep),
extract one representative frame as PNG, bounded by its own semaphore + a
per-process timeout + kill_on_drop. Noop when ffmpeg is absent/disabled, so
videos degrade gracefully to no thumbnail.
- ThumbnailRefreshHook.on_file_created routes video/* to
generate_video_thumbnails_background: stream the (decrypted, reassembled) blob
to a size- and time-bounded temp file on the data volume, extract a frame, and
reuse the shared render_and_persist_all_webp helper — so video thumbnails are
WebP, blob-hash keyed (dedup'd) and content-negotiated, exactly like photos.
- GET thumbnail serves the video's WebP to every client (byte-sniffed
Content-Type); a genuine miss returns 204.
- Config: OXICLOUD_ENABLE_VIDEO_THUMBNAILS (default true, needs ffmpeg detected
at startup) + OXICLOUD_FFMPEG_PATH / _CONCURRENCY / _TIMEOUT_SECS / _MAX_MB.
- Dockerfile installs ffmpeg in the runtime image.
- Frontend: drop the client-side generateVideoThumb/frameFromVideo re-download
path; the server is now the source of truth.
Benchmark (examples/bench_video_thumbnails.rs, needs ffmpeg): 4/4 codecs incl.
HEVC/.mov produce a thumbnail server-side (was 0% for HEVC); ~50-70 ms/frame in
the background; ~3.9 KB preview WebP; up to ~23x less per-first-view transfer on
the test corpus (far more on real multi-MB clips). Methodology in
benches/VIDEO-THUMB.md.
Hardening from an adversarial review: video render holds the decode_semaphore
like the image path; the ffmpeg scale filter bounds both dimensions; the blob
stream has a timeout; the temp file lives on the data volume; the size cap uses
saturating_mul.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Thumbnails are now generated eagerly as lossy WebP (the primary codec) and
served to clients that advertise `Accept: image/webp`; JPEG is kept as a lazy
fallback for older clients and NextCloud, generated on first request and then
cached like WebP.
- ThumbnailFormat{Webp,Jpeg} enum threaded through encode/render/generate, the
on-disk path ({hash}.webp / {hash}.jpg), the moka cache key
(file_id, size, format), and cleanup (both formats removed).
- file_handler: parse Accept -> format, format-keyed ETag, `Vary: Accept` on
every response (incl. 304) so shared caches never serve the wrong codec;
Content-Type is byte-sniffed (infer) so it always matches the bytes.
- preview_handler (NextCloud) pins JPEG.
- webp = "0.3" (vendored libwebp via cc, no system dependency).
WEBP_QUALITY=82, chosen via a quality sweep (bench Table E1): SSIM within
~0.005 of JPEG q80 (imperceptible at thumbnail scale) for ~62% fewer bytes. On
the photo-realistic bench corpus the full set (3 sizes x 3 photos) drops 65.6%
(213->73 KB); real photos with edges/text land nearer ~25-40%. Encode is +5ms,
paid once in the eager background generator (off the request path).
The bench corpus is now photo-realistic (per-channel sums of low-frequency
sinusoids) instead of white noise, which had distorted codec byte ratios.
Methodology + numbers in benches/WEBP.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The owner short-circuit in PgAclEngine::check ran a PK query
(SELECT user_id FROM storage.folders/files WHERE id=$1) on every authorization
check of a folder/file — the common case, since users mostly act on their own
resources. Memoise it in an owner_cache (moka, TTL 300s, 100k cap). The owner
column is immutable, so this is safe: the cache maps resource -> real owner and
can never grant a non-owner access (a different caller's owner==uid test fails
against the cached owner and falls through to grants); a hard-deleted resource
that briefly resolves to its former owner simply fails later at execution with
NotFound. The per-check sql_queries counter now increments only on a miss.
Removes 1 DB query + 1 pool-connection acquisition per owner check. Magnitude is
deployment-specific (query latency x whether the pool is contended); see
benches/ACL-OWNER-CACHE.md.
Also adds two DB perf-investigation harnesses, gated behind the `bench` feature
(need the dev Postgres; zero prod impact):
- examples/bench_db_pool.rs + benches/DB-POOL.md — pool size vs tail latency
- examples/bench_owner_cache.rs + benches/ACL-OWNER-CACHE.md — owner query vs cache
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Benchmark refuted the rayon-oversubscription hypothesis: throughput stayed flat
at the real operating point (14 permits) and PNG single-image latency regressed
66% when the 3-size resize was made sequential. The code was reverted; this
records the negative result in benches/BASELINE.md so it isn't retried (like the
dropped defer-Large task).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Replace the image crate's scalar resampler with fast_image_resize
(AVX2/SSE4.1/NEON) in a shared encode_thumbnail() helper. render_all now
converts to RGB8 once and SIMD-resizes the shared buffer per size. Lanczos3 for
downscaling, CatmullRom when upscaling (Lanczos rings on enlargement).
Also folds the duplicated path-variant generate_all_sizes_background into the
shared render path -- it had missed BOTH shrink-on-load and SIMD resizing -- so
every thumbnail path now goes through one optimised routine (no duplication).
Measured on 14 cores vs the post-1.5 state (benches/BASELINE.md):
- PNG 2.60x faster (33.6->12.9ms), GIF/WebP 1.25-1.6x: full-resolution decode
paths where the resize dominates, so SIMD helps most
- JPEG only ~7% (shrink-on-load already shrank the bitmap) but peak heap fell
another ~2.5x (17.6->7.1MB): tight RGB buffers, RGB conversion once
- quality SSIM 0.986-0.994 at identical dims (>=0.98 gate)
Thumbnails are now exactly max_dim on the long side (e.g. 400x266) vs the old
fit-within 399x266 -- a <=1px change, invisible under object-fit: cover.
Bench example gains an exact-dims quality reference + semaphore throughput table.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Shrink-on-load decoupled peak heap from source resolution (~18-25 MB per decode
regardless of MP), so the RAM ceiling that justified halving decode concurrency
is gone. max_concurrent_decodes() now defaults to all cores, with an
OXICLOUD_THUMBNAIL_DECODE_CONCURRENCY override for ops tuning.
Measured on the real service path (Semaphore + spawn_blocking), 14 cores:
- 12MP: 92.7 -> 133.7 photos/s (1.44x)
- 24MP: 49.5 -> 69.9 photos/s (1.41x)
peak heap unchanged; cpus*2 yields nothing, confirming cpus is the right ceiling
for CPU-bound work (the gap to 2x is rayon oversubscription -- Task 1.7).
Adds a semaphore-bounded throughput harness (Table D) to the bench example.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Decode JPEGs at the smallest DCT scale (1/8·1/4·1/2·1/1) whose long axis is
still ≥ the largest needed thumbnail (800px), via jpeg-decoder, instead of a
full-resolution decode through the image crate. The full-res bitmap — the
dominant time and RAM cost — is never materialised. PNG/GIF/WebP and unusual
JPEG colour spaces (CMYK / 16-bit grey) fall back to a full decode.
Extracts the shared decode + EXIF-orientation logic into decode_oriented(),
removing the duplication that existed between render_thumbnail_from_data and
render_all_thumbnails_from_data.
Measured on 14 cores (see benches/BASELINE.md):
- render_all 1.8-2.0× faster (12MP 111->61ms, 48MP 398->203ms)
- peak heap 5.5-14.8× lower, now decoupled from source MP (~18-25MB regardless)
- saturated throughput 3-3.6× (parallel efficiency 4.9×->8.5×)
- quality SSIM 0.987-0.999 (>=0.98 gate), PSNR 47-55dB
Also adds the Phase 0 benchmark harness (gated behind the `bench` feature, zero
prod impact): deterministic image corpus (src/bench_support.rs), criterion
latency bench (benches/thumbnails.rs), and a peak-RAM/throughput/SSIM harness
(examples/bench_thumbnails_mem.rs). Baseline + before/after in benches/BASELINE.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude