derived-blobs.md — consolidates several review rounds.
BLOCKER found while building the coverage matrix: the zero-ref manifest
sweep in dedup_gc (dedup_service.rs:2574) deletes a manifest when
`ref_count <= 0 OR NOT EXISTS (SELECT 1 FROM storage.files ...)`. That
OR hardcodes "storage.files is the only thing that can reference a
manifest", so a thumbnail manifest held only by content_derived_blobs
is deleted on the next GC run, its chunks dereferenced and the bytes
reaped. Promoted to prerequisite 0 and delivery step 2. It is also the
missing half of the unreconciled chunk_manifests.ref_count: that OR is
the hack that made the drift survivable.
Adds the 13-edge consistency coverage matrix (rows 1-6 and 13 covered,
7-11 not), and records that backend_consistency needs NO change — the
backend holds chunks, which neither new table references.
BlobReferenceSource correction: `ref_level()` was wrong because
FilesReferenceSource spans both levels (chunk for legacy manifest-less
rows, Blob for CDC rows). Replaced with
`ref_count_sql(level, alias) -> Option<String>`.
Also: migration of existing sidecar content; schema trim to the columns
nothing else owns (no size/format/codec/renderer; content_type kept as
non-key since it removes today's byte-sniffing); ext-{file_id}.jpg
corrected — the client generator ships and covers PDF, which has no
server-side rasteriser, so file_attached_blobs is required rather than
deferred; uploaded_by on the shares NOT NULL/no-FK convention; the
mermaid relation map; copy and version semantics with the
copy_file_satellites consolidation; the storage.files vs file_metadata
table-identity fix; DedupService -> BlobHandler recorded as decided.
NEW hidden-system.md — retires auth.users.image TEXT (inline base64
avatar, up to 512 KiB, already worked around with a narrow projection
after it was measured detoasting M avatars per group fan-out) in favour
of *_file_id pointers at ordinary storage.files rows in one shared
hidden system drive. Because storage.files is already a
BlobReferenceSource, a file pointer costs zero new reference sources
and zero new consistency edges. Records why the alternatives lose,
the drive's required properties (hidden at enumeration, trash off,
quota exempt, boot fail-fast), per-kind visibility in code, the
secrets exclusion rule, the avatar migration, and the future object
catalogue.
Docs only; no code or schema changes.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Edouard Vanbelle
07bb38eacb