---
id: pg-fix-dedupe-cleanup
name: Decode dedupe + small cleanups in queue/tx/notify (review 002 minor notes)
status: completed
depends_on: [pg-fix-tx-wake]
scope: narrow
risk: low
impact: component
level: implementation
tags: [wave-4-fixes, postgres-engine, cleanup]
---

## Description

Batch the wave-4 general review's minor notes that share files and are
too small for standalone tasks
(`docs/reviews/002-wave-4-general-review.md` §Minor notes + §Finding
6's queue bullet):

- **`job_from_row` is byte-for-byte duplicated** (`queue.rs:411` and
  `tx.rs:626`; only `pub(crate)` differs), and `get_job_tx` inlines
  the 18-column dead/live select column lists (`tx.rs:420-428,
  438-442`) duplicating `queue.rs`'s `live_columns()`/`dead_columns()`.
  Both files claim "one decode owner" in their doc comments; both are
  wrong. The `Job` shape is contract-pinned, so two owners is exactly
  where a shape edit goes wrong later. **Dedupe into one module** —
  `queue.rs` is the natural home; `tx.rs` imports it (as `tx.rs`
  already imports `stream_events_from_rows` from `stream.rs`). The
  doc comments must again tell the truth (one decode owner).
- **`queue.rs:71` doc fix (Finding 6)**: `sweep_expired` "returns the
  moved count" — it returns moved + retention-deleted (`queue.rs:720`).
  The SQLite twin returns the same sum (substrate `queue_ops.rs:232-243`),
  so the engines agree; only the doc is wrong. ("Single-statement
  atomic" is also inaccurate — it's the `in_tx` multi-statement
  frame.) Correct both claims.
- **`notify.rs:106-110`**: the closed-store error is built inline
  (`Error::database(std::io::Error::other(...))`) instead of the
  shared `database_error` helper — one duplicate of the one message.
  Route it through the helper.
- **`bridge_capacity()`** (`notify.rs:137-139`) is a function
  returning a constant — a `const` says it plainly. Convert (keep the
  doc comment's rationale on the const).

No behavior changes anywhere in this task — it is dedupe + doc
truth-telling. All existing tests must pass unchanged; where a test
asserts on the moved-count semantics, it already pins the sum (the
doc was the only liar).

**Depends on `pg-fix-tx-wake`**: that task edits `tx.rs`'s
publish/enqueue paths; this task restructures `tx.rs`'s decode side —
landing after avoids touching the same file regions blind.

## Acceptance Criteria

- [ ] `job_from_row` has one owner (`queue.rs`); `tx.rs` imports it;
      both files' "one decode owner" doc claims are true
- [ ] `get_job_tx`'s dead/live column lists reuse `queue.rs`'s
      `live_columns()`/`dead_columns()` (no inlined duplicates)
- [ ] `sweep_expired`'s doc states the moved + retention-deleted sum
      and the `in_tx` frame (matching the SQLite twin's semantics)
- [ ] `notify.rs`'s closed-store error routes through
      `database_error`; `bridge_capacity` is a `const`
- [ ] Zero behavior change: the full pg lib suite green against the
      harness server, unchanged assertions
- [ ] `cargo clippy --all-targets -- -D warnings`, fmt clean; gates
      green server-less

## References

- docs/reviews/002-wave-4-general-review.md §Minor notes + §Finding 6
  (the queue bullet)
- docs/architecture/core-contract.md (the pinned `Job` shape — why one
  decode owner matters)
- tasks/pg-engine-queues.md, tasks/pg-engine-seam-tx.md (the tasks of
  record for the touched files)

## Notes

- The dedupe landed as the task pinned: `job_from_row` is now owned by
  `queue.rs` (`pub(crate)`), `tx.rs` imports it; queue.rs's
  `live_columns()`/`dead_columns()` went `pub(crate)` so `get_job_tx`
  reuses them (the `format!`-bound `{dead}`/`{live}` select strings are
  byte-identical to the inlined lists, so zero SQL change). Tx-side
  imports ride the existing `crate::queue` module edge — fine
  crate-internally (queue.rs already imports tx.rs's
  `encode_payload_bytes`/`enqueue_row`; Rust module cycles are legal
  within a crate).
- Doc truth-telling choices: queue.rs's `job_from_row` doc now states
  the one owner explicitly ("the tx reads (`crate::tx`) ... import it");
  tx.rs's trailing decode-owner comment now names both decode owners
  (stream decode in `stream.rs`, job decode in `queue.rs`) under
  ADR-012 §2; the removed tx.rs duplicate carried `JobState`'s only
  remaining use, so that import was dropped. queue.rs's `sweep_expired`
  module-doc bullet now states the moved + retention-deleted sum and
  the `in_tx` multi-statement frame (matching the SQLite twin's
  semantics — the code already pinned the sum).
- `bridge_capacity()` → `const BRIDGE_CAPACITY` with the rationale doc
  comment carried; the closed-store error in `listen` now routes
  through `database_error` (it was the only inline duplicate;
  import already present).
- No behavior change anywhere: the select SQL strings, error shapes,
  and the bridge capacity value are identical.

## Summary

Deduped the pg engine's job-row decode and cleaned the wave-4 minor
notes (review 002): `job_from_row` has one owner (`queue.rs`), `get_job_tx`
reuses `live_columns()`/`dead_columns()` instead of inlining the
18-column lists, `sweep_expired`'s doc states the moved +
retention-deleted sum in the `in_tx` frame (the sum the SQLite twin
returns), `notify.rs`'s closed-store error routes through
`database_error`, and `bridge_capacity` is a `const`. Verified: pg
suite 140/140 green against the harness server (`pglo-poc` :15432)
and 140/140 server-less, unchanged assertions; workspace
`cargo build` / `cargo clippy --all-targets -- -D warnings` /
`cargo fmt --check` / `cargo test --workspace` all clean.