T3: persisted per-(sink,partition) watermark store keyed by logical path#155
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philcunliffe merged 1 commit intoJun 25, 2026
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Add `src/core/sinks/watermarks.js`, the shared incremental-read watermark
store for the forward and blob sinks (LLP 0042 task T3). Files live at
`<stateDir>/watermarks/<dataset>/<partition-key>.json` and carry the
versioned `{ continuation, exportedRowCount, updatedAt }` record.
The key is derived from the partition's stable LOGICAL path
(`datasets/<dataset>/<partition...>` relative to cacheRoot), never the
physical `tableDir` inside it — the hinge of design constraint (B): the
watermark reads straight through a compaction generation swap and a
retention front-prune. `write` is atomic write-rename (the
`writeCursor`/`writeProgress`/`ingest-seq.js` idiom); a corrupt or absent
record reads back as null so a sink re-exports from the start
(at-least-once + downstream dedup) rather than silently skipping rows.
Adds `SinkWatermarkKey`/`SinkWatermarkRecord`/`SinkWatermarkStore` types,
anchors LLP 0040 §3 (`#watermark-contract`), and a unit suite covering key
derivation (logical-not-tableDir, nesting, sanitize, sentinel, escape
guard), round-trip, in-place advance, atomic-no-temp, malformed-token
rejection, and corrupt-file null.
@ref LLP 0040#watermark-contract
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Task-Id: T3
philcunliffe
merged commit 88d6841
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integration/incremental-sink-reads
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Implements task T3 of incremental-sink-reads (LLP 0042).
Adds
src/core/sinks/watermarks.js: the shared per-(sink instance, partition)incremental-read watermark store at<stateDir>/watermarks/<dataset>/<partition-key>.json, keyed by the stable LOGICAL partition path (not the physicaltableDir), with atomic write-rename. Includes types and a unit suite. Consumed by T4 (forward sink) and T5 (blob sink).Checks:
npm test(1418 pass),npm run typecheck(clean),npm run lint(clean).Task-Id: T3