# Scan Metrics Schema

Sprint: `SPRINT_3406_0001_0001_metrics_tables`  
Task: `METRICS-3406-013`  
Working Directory: `src/Scanner/__Libraries/StellaOps.Scanner.Storage/Postgres/Migrations/`

## Overview

The scan metrics schema provides relational PostgreSQL tables for tracking Time-to-Evidence (TTE) and scan performance metrics. This is a hybrid approach where metrics are stored in PostgreSQL while replay manifests remain in the document store.

## Tables

### `scanner.scan_metrics`

Primary table for per-scan metrics.

| Column | Type | Description |
|--------|------|-------------|
| `metrics_id` | UUID | Primary key |
| `scan_id` | UUID | Unique scan identifier |
| `tenant_id` | UUID | Tenant identifier |
| `surface_id` | UUID | Optional attack surface identifier |
| `artifact_digest` | TEXT | Artifact content hash |
| `artifact_type` | TEXT | Type: `oci_image`, `tarball`, `directory`, `other` |
| `replay_manifest_hash` | TEXT | Reference to replay manifest in document store |
| `findings_sha256` | TEXT | Findings content hash |
| `vex_bundle_sha256` | TEXT | VEX bundle content hash |
| `proof_bundle_sha256` | TEXT | Proof bundle content hash |
| `sbom_sha256` | TEXT | SBOM content hash |
| `policy_digest` | TEXT | Policy version hash |
| `feed_snapshot_id` | TEXT | Feed snapshot identifier |
| `started_at` | TIMESTAMPTZ | Scan start time |
| `finished_at` | TIMESTAMPTZ | Scan completion time |
| `total_duration_ms` | INT | TTE in milliseconds (generated) |
| `t_ingest_ms` | INT | Ingest phase duration |
| `t_analyze_ms` | INT | Analyze phase duration |
| `t_reachability_ms` | INT | Reachability phase duration |
| `t_vex_ms` | INT | VEX phase duration |
| `t_sign_ms` | INT | Sign phase duration |
| `t_publish_ms` | INT | Publish phase duration |
| `package_count` | INT | Number of packages analyzed |
| `finding_count` | INT | Number of findings |
| `vex_decision_count` | INT | Number of VEX decisions |
| `scanner_version` | TEXT | Scanner version |
| `scanner_image_digest` | TEXT | Scanner container digest |
| `is_replay` | BOOLEAN | Replay mode flag |
| `created_at` | TIMESTAMPTZ | Record creation time |

### `scanner.execution_phases`

Detailed phase execution tracking.

| Column | Type | Description |
|--------|------|-------------|
| `id` | BIGSERIAL | Primary key |
| `metrics_id` | UUID | Foreign key to `scan_metrics` |
| `phase_name` | TEXT | Phase: `ingest`, `analyze`, `reachability`, `vex`, `sign`, `publish`, `other` |
| `phase_order` | INT | Execution order |
| `started_at` | TIMESTAMPTZ | Phase start time |
| `finished_at` | TIMESTAMPTZ | Phase completion time |
| `duration_ms` | INT | Duration in milliseconds (generated) |
| `success` | BOOLEAN | Phase success status |
| `error_code` | TEXT | Error code if failed |
| `error_message` | TEXT | Error message if failed |
| `phase_metrics` | JSONB | Phase-specific metrics |

## Views

### `scanner.scan_tte`

Time-to-Evidence view with phase breakdowns.

```sql
SELECT
    metrics_id,
    scan_id,
    tte_ms,
    tte_seconds,
    ingest_percent,
    analyze_percent,
    reachability_percent,
    vex_percent,
    sign_percent,
    publish_percent
FROM scanner.scan_tte
WHERE tenant_id = :tenant_id;
```

### `scanner.tte_stats`

Hourly TTE statistics with SLO compliance.

```sql
SELECT
    hour_bucket,
    scan_count,
    tte_avg_ms,
    tte_p50_ms,
    tte_p95_ms,
    slo_p50_compliance_percent,
    slo_p95_compliance_percent
FROM scanner.tte_stats
WHERE tenant_id = :tenant_id;
```

## Functions

### `scanner.tte_percentile`

Calculate TTE percentile for a tenant.

```sql
SELECT scanner.tte_percentile(
    p_tenant_id := :tenant_id,
    p_percentile := 0.95,
    p_since := NOW() - INTERVAL '7 days'
);
```

## Indexes

| Index | Columns | Purpose |
|-------|---------|---------|
| `idx_scan_metrics_tenant` | `tenant_id` | Tenant queries |
| `idx_scan_metrics_artifact` | `artifact_digest` | Artifact lookups |
| `idx_scan_metrics_started` | `started_at` | Time-range queries |
| `idx_scan_metrics_surface` | `surface_id` | Surface queries |
| `idx_scan_metrics_replay` | `is_replay` | Filter replays |
| `idx_scan_metrics_tenant_started` | `tenant_id, started_at` | Compound tenant+time |
| `idx_execution_phases_metrics` | `metrics_id` | Phase lookups |
| `idx_execution_phases_name` | `phase_name` | Phase filtering |

## SLO Thresholds

Per the advisory section 13.1:

| Metric | Target |
|--------|--------|
| TTE P50 | < 120 seconds |
| TTE P95 | < 300 seconds |

## Usage Examples

### Get TTE for recent scans

```sql
SELECT scan_id, tte_ms, tte_seconds
FROM scanner.scan_tte
WHERE tenant_id = :tenant_id
  AND NOT is_replay
ORDER BY started_at DESC
LIMIT 100;
```

### Check SLO compliance

```sql
SELECT
    hour_bucket,
    slo_p50_compliance_percent,
    slo_p95_compliance_percent
FROM scanner.tte_stats
WHERE tenant_id = :tenant_id
  AND hour_bucket >= NOW() - INTERVAL '24 hours';
```

### Phase breakdown analysis

```sql
SELECT
    phase_name,
    AVG(duration_ms) as avg_ms,
    PERCENTILE_CONT(0.95) WITHIN GROUP (ORDER BY duration_ms) as p95_ms
FROM scanner.execution_phases ep
JOIN scanner.scan_metrics sm ON ep.metrics_id = sm.metrics_id
WHERE sm.tenant_id = :tenant_id
  AND sm.started_at >= NOW() - INTERVAL '7 days'
GROUP BY phase_name
ORDER BY phase_order;
```

## Migration

Migration file: `src/Scanner/__Libraries/StellaOps.Scanner.Storage/Postgres/Migrations/004_scan_metrics.sql`

Apply with:
```bash
psql -d stellaops -f 004_scan_metrics.sql
```

## Related

- [Database Specification](./SPECIFICATION.md)
- [Determinism Advisory §13.1](../product-advisories/14-Dec-2025%20-%20Determinism%20and%20Reproducibility%20Technical%20Reference.md)
- [Scheduler Schema](./schemas/scheduler.sql)