---
phase: 02-storage-and-ddl
plan: 02-04
task: 2
total_tasks: 2
status: completed
last_updated: 2026-02-24T14:38:53.989Z
---

<current_state>
Plan 02-04 (DDL-05 persistence fix) is CODE COMPLETE and committed. Both tasks done.
The sidecar persistence approach works — all tests pass. What remains is wrapping up
the plan: writing 02-04-SUMMARY.md, updating STATE.md/ROADMAP.md, and running the
phase verifier to close out Phase 2.
</current_state>

<completed_work>
- Task 1: Resolve host DB path via PRAGMA database_list — DONE (commit 1e24914, refined in 824c60e)
- Task 2: Persistence across restart — DONE (commit 824c60e)
  - Tried try_clone() background thread — deadlocks (DuckDB execution locks during invoke)
  - Tried Connection::open(path) background thread — blocks on file-level lock
  - SOLUTION: Sidecar file persistence — invoke writes HashMap as JSON to <db>.semantic_views
    via plain file I/O; init_catalog reads sidecar on next load and syncs into DuckDB table
  - SQLLogicTest restart section passes end-to-end
- Planning docs: v0.2 requirement captured for pragma_query_t replacement (commit 3ff6f9d)
</completed_work>

<remaining_work>
1. Write 02-04-SUMMARY.md (plan completion doc)
2. Update STATE.md — mark Phase 2 complete, update progress bar
3. Update ROADMAP.md — mark Phase 2 plans done
4. Run phase verifier for Phase 2
5. Transition to Phase 3 (Expansion Engine)
</remaining_work>

<decisions_made>
- **Sidecar persistence for v0.1**: DuckDB holds execution locks during scalar invoke.
  try_clone() deadlocks (same instance), Connection::open(path) blocks on file lock.
  Sidecar JSON file is the only deadlock-free pure-Rust option. Accepted as temporary —
  v0.2 C++ shim will use pragma_query_t callbacks (FTS extension pattern).
- **PRAGMA filter fix**: Python's DuckDB names DBs by filename stem, not "main".
  Filter changed from `name == "main"` to `find first non-empty file path`.
- **Sidecar wins on conflict**: When init_catalog reads both table and sidecar,
  sidecar data replaces table contents (it reflects the latest session state).
</decisions_made>

<blockers>
None — all blockers resolved.
</blockers>

<context>
Phase 2 code is done. All 5 DDL requirements (DDL-01 through DDL-05) are satisfied:
- DDL-01: define_semantic_view registers views ✓
- DDL-02: drop_semantic_view removes views ✓
- DDL-03: list_semantic_views returns registered views ✓
- DDL-04: describe_semantic_view returns definition fields ✓
- DDL-05: definitions survive file-backed restart ✓ (sidecar persistence)

16 Rust unit tests pass. 2 SQLLogicTest files pass (including restart section).
Zero clippy warnings.

The v0.2 requirement to replace sidecar with pragma_query_t is captured in PROJECT.md.
</context>

<next_action>
Resume with: /gsd:resume-work

Next steps are administrative — write SUMMARY, update STATE/ROADMAP, run verifier,
then transition to Phase 3 (Expansion Engine).
</next_action>
