---
phase: 34.1-close-ddl-gaps-vs-snowflake
verified: 2026-03-22T00:00:00Z
status: passed
score: 12/12 must-haves verified
gaps: []
human_verification: []
---

# Phase 34.1: Close DDL Gaps vs Snowflake Verification Report

**Phase Goal:** Close DDL gaps vs Snowflake: ALTER SEMANTIC VIEW, SHOW SEMANTIC DIMENSIONS/FACTS/METRICS
**Verified:** 2026-03-22
**Status:** passed
**Re-verification:** No — initial verification

---

## Goal Achievement

### Observable Truths

| #  | Truth | Status | Evidence |
|----|-------|--------|----------|
| 1  | ALTER SEMANTIC VIEW old_name RENAME TO new_name renames the view | VERIFIED | `phase34_1_alter_rename.test` Test 1 exercises full rename; `alter.rs` bind() removes old, inserts new via `catalog_rename` |
| 2  | ALTER SEMANTIC VIEW IF EXISTS missing_name RENAME TO x is a silent no-op | VERIFIED | Test 4 in `phase34_1_alter_rename.test`; `alter.rs` bind() returns Ok with no mutation when `if_exists=true` and old_name absent |
| 3  | ALTER RENAME to an existing name returns an error | VERIFIED | Test 5 in `phase34_1_alter_rename.test`; `catalog_rename` rolls back on conflict |
| 4  | Renamed view persists across database restart | VERIFIED | `persist_rename` (DELETE+INSERT in `semantic_layer._definitions`) is called before in-memory update; `persist_conn` wired in `lib.rs` line 426 |
| 5  | Renamed view is queryable under its new name | VERIFIED | Test 1 queries `semantic_view('revenue_view', ...)` after rename and returns expected rows |
| 6  | SHOW SEMANTIC DIMENSIONS IN view_name lists all dimensions for that view | VERIFIED | `phase34_1_show_commands.test` Test 1; `ShowSemanticDimensionsVTab` collects dims and returns 5-column schema |
| 7  | SHOW SEMANTIC DIMENSIONS (without IN) lists dimensions across all views | VERIFIED | Test 2; `ShowSemanticDimensionsAllVTab` iterates all catalog entries |
| 8  | SHOW SEMANTIC METRICS IN view_name and cross-view forms work | VERIFIED | Tests 3 and 4; `ShowSemanticMetricsVTab` / `ShowSemanticMetricsAllVTab` in `show_metrics.rs` |
| 9  | SHOW SEMANTIC FACTS IN view_name and cross-view forms work | VERIFIED | Tests 5 and 6; `ShowSemanticFactsVTab` / `ShowSemanticFactsAllVTab` in `show_facts.rs` (4-column schema, no data_type) |
| 10 | Each SHOW command returns structured columns matching plan spec | VERIFIED | DIMS/METRICS: 5 columns (semantic_view_name, name, expr, source_table, data_type); FACTS: 4 columns (no data_type); confirmed in bind_output_columns helpers |
| 11 | SHOW SEMANTIC DIMENSIONS IN view FOR METRIC metric returns only fan-trap-safe dimensions | VERIFIED | `phase34_1_show_dims_for_metric.test` Tests 2 and 3 confirm item_qty excluded for order_total metric, all dims included for line_item_sum |
| 12 | Derived metrics resolve source tables transitively for FOR METRIC filtering | VERIFIED | Test 6 (derived_sv): double_total derives from order_total; `collect_derived_metric_source_tables` resolves source table o; customer_name correctly included |

**Score:** 12/12 truths verified

---

### Required Artifacts

| Artifact | Expected | Status | Details |
|----------|----------|--------|---------|
| `src/ddl/alter.rs` | AlterRenameVTab, AlterRenameState, persist_rename | VERIFIED | 169 lines; substantive VTab implementation with write-first persistence |
| `src/catalog.rs` | catalog_rename function | VERIFIED | Lines 169-185; atomic remove+insert with rollback on conflict |
| `src/parse.rs` | AlterRename/AlterRenameIfExists/ShowDimensions/ShowMetrics/ShowFacts DdlKind variants; FOR METRIC rewrite | VERIFIED | DdlKind enum at lines 34-38; rewrite logic at lines 296-373 |
| `src/ddl/show_dims.rs` | ShowSemanticDimensionsVTab + ShowSemanticDimensionsAllVTab | VERIFIED | 199 lines; two VTab structs with shared BindData/InitData |
| `src/ddl/show_metrics.rs` | ShowSemanticMetricsVTab + ShowSemanticMetricsAllVTab | VERIFIED | 201 lines; mirrors show_dims.rs pattern |
| `src/ddl/show_facts.rs` | ShowSemanticFactsVTab + ShowSemanticFactsAllVTab | VERIFIED | 194 lines; 4-column schema (no data_type, matching Fact model) |
| `src/ddl/show_dims_for_metric.rs` | ShowDimensionsForMetricVTab with fan-trap filtering | VERIFIED | 336 lines; full LCA-based fan-trap analysis via is_dimension_reachable_for_metric |
| `test/sql/phase34_1_alter_rename.test` | SQL logic tests for DDL-01, DDL-02 | VERIFIED | 155 lines; 8 test cases including edge cases |
| `test/sql/phase34_1_show_commands.test` | SQL logic tests for DDL-03 through DDL-06 | VERIFIED | 152 lines; 8 test cases including cross-view and error paths |
| `test/sql/phase34_1_show_dims_for_metric.test` | SQL logic tests for DDL-07 | VERIFIED | 191 lines; 7 test cases including fan-trap, derived metric, case-insensitivity |

---

### Key Link Verification

| From | To | Via | Status | Details |
|------|----|-----|--------|---------|
| `src/parse.rs` | `src/ddl/alter.rs` | rewrite to `SELECT * FROM alter_semantic_view_rename('old','new')` | WIRED | `function_name` returns `alter_semantic_view_rename` at line 218; AlterRename branch at line 353 |
| `src/parse.rs` | `src/ddl/show_dims_for_metric.rs` | rewrite to `SELECT * FROM show_semantic_dimensions_for_metric('view','metric')` | WIRED | `rewrite_show_dims_for_metric` produces this at line 261; triggered from ShowDimensions branch at line 339 |
| `src/ddl/alter.rs` | `src/catalog.rs` | `catalog_rename` call at bind time | WIRED | `use crate::catalog::catalog_rename` at line 10; called at line 129 |
| `src/ddl/show_dims_for_metric.rs` | `src/expand.rs` | `ancestors_to_root`, `collect_derived_metric_source_tables`, `suggest_closest` | WIRED | All imported at line 10; `pub(crate)` visibility confirmed in expand.rs lines 936 and 1112 |
| `src/ddl/show_dims_for_metric.rs` | `src/graph.rs` | `RelationshipGraph::from_definition` | WIRED | `use crate::graph::RelationshipGraph` at line 11; called at line 244 |
| `src/lib.rs` | `src/ddl/alter.rs` | `register_table_function_with_extra_info::<AlterRenameVTab>` (two registrations) | WIRED | Lines 429-442; both `alter_semantic_view_rename` and `alter_semantic_view_rename_if_exists` registered |
| `src/lib.rs` | `src/ddl/show_dims.rs` | `register_table_function_with_extra_info::<ShowSemanticDimensionsVTab>` + AllVTab | WIRED | Lines 456-464 |
| `src/lib.rs` | `src/ddl/show_dims_for_metric.rs` | `register_table_function_with_extra_info::<ShowDimensionsForMetricVTab>` | WIRED | Lines 466-470 |
| `src/lib.rs` | `src/ddl/show_metrics.rs` | `register_table_function_with_extra_info::<ShowSemanticMetricsVTab>` + AllVTab | WIRED | Lines 472-480 |
| `src/lib.rs` | `src/ddl/show_facts.rs` | `register_table_function_with_extra_info::<ShowSemanticFactsVTab>` + AllVTab | WIRED | Lines 482-490 |
| `src/ddl/mod.rs` | all new modules | `pub mod alter; pub mod show_dims; pub mod show_dims_for_metric; pub mod show_facts; pub mod show_metrics` | WIRED | Lines 1-9 of mod.rs |
| `test/sql/TEST_LIST` | all three test files | listed at lines 13-15 | WIRED | All three phase34_1 tests are included in the runner list |

---

### Requirements Coverage

| Requirement | Source Plan | Description | Status | Evidence |
|-------------|------------|-------------|--------|----------|
| DDL-01 | 34.1-01 | ALTER SEMANTIC VIEW old RENAME TO new renames the view in catalog and persistent storage | SATISFIED | `alter.rs` bind() calls `persist_rename` then `catalog_rename`; sqllogictest Test 1 passes |
| DDL-02 | 34.1-01 | ALTER SEMANTIC VIEW IF EXISTS missing RENAME TO x is a silent no-op | SATISFIED | `if_exists=true` path in `alter.rs` returns Ok without mutation; sqllogictest Test 4 passes |
| DDL-03 | 34.1-02 | SHOW SEMANTIC DIMENSIONS IN view_name lists dimensions with 5-column schema | SATISFIED | `ShowSemanticDimensionsVTab` returns `semantic_view_name, name, expr, source_table, data_type`; sqllogictest Test 1 passes |
| DDL-04 | 34.1-02 | SHOW SEMANTIC DIMENSIONS (without IN) lists dimensions across all views | SATISFIED | `ShowSemanticDimensionsAllVTab` iterates all catalog entries; sqllogictest Test 2 passes |
| DDL-05 | 34.1-02 | SHOW SEMANTIC METRICS [IN view_name] with same column schema as SHOW DIMENSIONS | SATISFIED | `ShowSemanticMetricsVTab` + All variant; sqllogictest Tests 3 and 4 pass |
| DDL-06 | 34.1-02 | SHOW SEMANTIC FACTS [IN view_name] with 4-column schema (no data_type) | SATISFIED | `ShowSemanticFactsVTab` + All variant; 4-column schema (no data_type); sqllogictest Tests 5 and 6 pass |
| DDL-07 | 34.1-03 | SHOW SEMANTIC DIMENSIONS IN view FOR METRIC metric returns fan-trap-safe dimensions only | SATISFIED | `ShowDimensionsForMetricVTab` with LCA-based fan-trap filtering; sqllogictest Tests 2, 3, 6 cover fan-trap and derived metric scenarios |

No orphaned requirements detected. All 7 DDL-0x IDs assigned to Phase 34.1 in REQUIREMENTS.md are claimed by plans and verified.

---

### Anti-Patterns Found

None. No TODOs, FIXMEs, placeholders, empty implementations, or unconnected stubs found in any of the five new source files.

---

### Human Verification Required

None. All behaviors are testable via sqllogictests and have been verified programmatically. The full quality gate (`cargo test`, `just test-sql`, `just test-ducklake-ci`) passes:

- `cargo test`: 42 unit + 5 proptest + 1 doc test — all pass
- `just test-sql`: 16 sqllogictests — all pass (including the 3 new phase34_1 tests)
- `just test-ducklake-ci`: 6 DuckLake integration tests — all pass

---

### Summary

Phase 34.1 fully achieves its goal. All 7 DDL requirements (DDL-01 through DDL-07) are implemented with substantive, non-stub code and verified by dedicated sqllogictest suites. The full pipeline — parse detection, SQL rewrite, VTab binding, catalog mutation, and persistence — is wired end-to-end across `parse.rs`, `ddl/alter.rs`, `ddl/show_dims.rs`, `ddl/show_metrics.rs`, `ddl/show_facts.rs`, `ddl/show_dims_for_metric.rs`, `catalog.rs`, `graph.rs`, `expand.rs`, and `lib.rs`. The fan-trap-aware `SHOW SEMANTIC DIMENSIONS FOR METRIC` implementation uses a full LCA-path analysis with cardinality-direction checks, not a simplified stub.

---

_Verified: 2026-03-22_
_Verifier: Claude (gsd-verifier)_
