writeonce/docs/stories/language-runtime-database/33-single-file-db.md
shoney.arickathil c0b0dbb846 docs: audit all markdown against the code, fix findings, flatten status folders
- README: shipped concurrency/HTTP/WebSockets sat in the roadmap as "not yet
  available"; "no package manager" contradicted [deps]; the deps example
  would not have compiled (the key IS the module name)
- runtime/README: leads with wovm, wo-rt.c demoted to a historical section;
  dropped 2 nonexistent recipes, crates/rt, @gc refcounting, 13 suites -> 18
- employee + log-watcher READMEs claimed "does not compile"; both are gates
- error catalog: +10 emitted codes incl WO-E250, the only diagnostic the
  shipped query surface raises; recorded why the sweep rotted
- language-surface: group-by parses, then the typechecker refuses it
- 00-code-review + 00-link-audit re-run; history kept, not rewritten
- 48 dead Rust-era exploration links de-linked rather than re-pointed (their
  prose names the retired plan by number); successor map -> discarded.md
- 08-project-structure: compiler/plan/ never existed; corpus has 9 dirs, 5 empty
- releasing.md: dropped a --draft step the workflow never had
- new docs/00-doc-audit.md: findings + disposition, incl one row where the
  audit was wrong and the doc it accused was right
- status folders removed: 34 stories flat, status only in frontmatter; 252
  links recomputed from resolved paths; board/board-views/structure retaught
- story 24 -> in-progress, since frontmatter is now the only truth
- new iteration 38: fs mutation verbs + net.connect, the two capability
  families no iteration owned
- new iteration 39: gofiber/fiber v3.5.0 parity study. The ledger called
  CSRF/sessions unblocked by iteration 34's HMAC, but the runtime has no
  source of randomness at all
- linkcheck skips .dev/.superpowers: 0 broken paths, 0 bad anchors

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-26 19:20:22 +02:00

73 lines
3.2 KiB
Markdown

---
iteration: "33"
status: refine
---
# Iteration 33 — `WO_DATA=<path>.db`: the persistent store as one file
> Format: `product/story-iteration-template`. Part of
> [Story — one language, one runtime, one database, one binary](00-story.md).
>
> **Inserted 2026-08-22** (developer ask: "can the persistent db be in
> file.db form?"). The truth is already almost there: `WO_DATA=<dir>`
> holds exactly ONE file (`shard-0.wal`) — the entire persistent state,
> since RAM is authoritative and no data pages exist. This iteration
> makes the surface say so: point `WO_DATA` at a file and THAT file is
> the store. Small, driver-only, independent of the concurrency chain.
## Goals
- **`WO_DATA=<path>` accepts a file path.** A path that is not an
existing directory is treated as THE wal file (`app.db`,
`store.wo.db` — the name is the operator's). The directory form stays
and keeps meaning `<dir>/shard-0.wal` — every existing deployment and
gate is byte-identical.
- **One file remains the whole truth at any core count** — stage 3 made
the WAL owner-shard-only (shard 0 is the sole writer), so nothing
multi-shard ever adds a second file.
- **The contract says it out loud**: `04-db-binding.md` documents the
file form, and documents honestly that the file is an append-only log
that grows until iteration 32 lands.
## Acceptance Criteria
- **Given** `WO_DATA=/tmp/app.db` (no such directory), **when** a
program seeds, restarts, and verifies, **then** replay is byte-true
and `/tmp/app.db` is the only artifact on disk.
- **Given** `WO_DATA=<dir>` (existing directory), **when** the same
program runs, **then** behavior is byte-identical to today —
`<dir>/shard-0.wal`, every standing gate unchanged.
- **Given** the db-bench durability legs pointed at the file form,
**when** the restart proof and kill -9 battery run, **then** every
guarantee holds identically (the file IS the same WAL, only named by
the operator).
## Out Of Scope
- A paged database file (SQLite's shape) — RAM is authoritative; the
disk story is the WAL, full stop.
- Checkpoint/compaction — [iteration 32](32-wal-checkpoint.md)'s; its
rename-swap (write snapshot+tail to a NEW file, fsync, `rename()`
over the old) is exactly what keeps the single-file promise crash-safe
when it lands. 33 before or after 32 works; landing 33 first means
32's spec inherits the file form as a stated constraint.
- Multiple stores per process, attach-by-file — held iteration 20's
territory.
## Info
- The whole change is `runtime/src/main.c`'s hardcoded
`snprintf("%s/shard-0.wal", dir)` growing a stat-based fork
(directory → today's path; otherwise → the path itself), plus a gate
check and the binding-doc note. No engine, no WAL format, no
compiler.
- Fork for the (tiny) spec: what does a NONEXISTENT path mean? Leaning:
a path whose parent exists and that does not end in `/` is a file to
create; a trailing `/` or existing directory keeps the directory
form. Refusing ambiguity loudly (WO exit 2) beats guessing.
## Proposed Solution
Small enough for a bounded slice: brainstorm the one fork in chat,
implement driver + db-bench file-form leg + docs in one pass, gates
green. No plan document needed unless it grows.