# YachtMemory Source Catalog v2 — Concurrency Review 0.1.1

**REVIEW / isolated test only.** This is a correction of the test fixtures of review 0.1.0, NOT a production receiver change.

## Why 0.1.0 failed

Phase D sent two fresh manifests at revision 1, already the active revision. The test did not isolate receipt-sequence contention. Database inspection showed only existing receipt sequences 1–4 and active revision 1. No receipt at sequence 20.

## Changes

- New synthetic vessel UUID `a20b89f5-1fd9-42af-8919-7db720aa8c31`, unique baseline snapshot UUID; no cleanup of old review records.
- Conflict fixtures use different valid staged revisions **2 and 3**, one shared outbox `seq_no=20`, separate snapshot UUIDs and hashes. They may be staged after revision 1 without activation. Exactly one must commit.
- Distinct-sequence fixtures use revisions **4 and 5** and separate snapshot UUIDs.
- Whole payload strings and envelope hashes regenerated deterministically.
- On success or failure the test logs persist under `/tmp/ym-concurrency-011-*`; no automatic deletion. Test script is deliberately one-shot.
- Additional check compares the winning database receipt hash with the corresponding fixture.
- The receiver is byte-identical to the previously validated review 0.1.0 (`sha256 ba97aebcf67f2d679c0a622373754db1a6380b9bdf749c894dcaf22ef9698966`).

## Review first (no DB writes)

```bash
cd /var/www/app.yachtmemory.net/YM-Source-Catalog-v2-Concurrency-0.1.1-REVIEW
php -l receiver/ym-sync-catalog-v2-atomic-review.php
bash -n tests/mysql_concurrency_test_review.sh
python3 -m unittest discover -s tests -v
sha256sum receiver/ym-sync-catalog-v2-atomic-review.php
cat tests/mysql_concurrency_test_review.sh
```

## Later explicit MySQL test (one-shot, not yet run)

```bash
bash tests/mysql_concurrency_test_review.sh
```

Uses **only** `yachtmemory_catalog_v2_test`, requires existing `sync_receipts` and sudo mysql. Does not affect production receiver, controller, SilentMessDB or Wildbad. Parallel tests do not claim to establish network replay or full fleet-scale load safety.