# Sprint: SPRINT_20260117_029_Runbook_coverage_expansion
# Task: RUN-001 - PostgreSQL Operations Runbook
# PostgreSQL Database Runbook (dev-mock ready)

Status: PRODUCTION-READY (2026-01-17 UTC)

## Scope
PostgreSQL database operations including monitoring, maintenance, backup/restore, and common incident handling for Stella Ops deployments.

---

## Pre-flight Checklist

### Environment Verification
```bash
# Check database connection
stella db ping

# Verify connection pool health
stella doctor --check check.postgres.connectivity,check.postgres.pool

# Check migration status
stella db migrations status
```

### Metrics to Watch
- `stella_postgres_connections_active` - Active connections (should be < 80% of max)
- `stella_postgres_query_duration_seconds` - P99 query latency (target: < 100ms)
- `stella_postgres_pool_waiting` - Connections waiting for pool (should be 0)

---

## Standard Procedures

### SP-001: Daily Health Check

**Frequency:** Daily or on-demand
**Duration:** ~5 minutes

1. Run comprehensive health check:
   ```bash
   stella doctor --category database --format json > /tmp/db-health-$(date +%Y%m%d).json
   ```

2. Review slow queries from last 24h:
   ```bash
   stella db queries --slow --period 24h --limit 20
   ```

3. Check replication status (if applicable):
   ```bash
   stella db replication status
   ```

4. Verify backup completion:
   ```bash
   stella backup status --type database
   ```

### SP-002: Connection Pool Tuning

**When:** Pool exhaustion alerts or high wait times

1. Check current pool usage:
   ```bash
   stella db pool stats --detailed
   ```

2. Identify connection-holding queries:
   ```bash
   stella db queries --active --sort duration
   ```

3. Adjust pool size (if needed):
   ```bash
   # Review current settings
   stella config get Database:MaxPoolSize
   
   # Increase pool size
   stella config set Database:MaxPoolSize 150
   
   # Restart affected services
   stella service restart --service release-orchestrator
   ```

4. Verify improvement:
   ```bash
   stella db pool watch --duration 5m
   ```

### SP-003: Backup and Restore

**Backup:**
```bash
# Create immediate backup
stella backup create --type database --name "pre-upgrade-$(date +%Y%m%d)"

# Verify backup
stella backup verify --latest
```

**Restore:**
```bash
# List available backups
stella backup list --type database

# Restore to specific point (CAUTION: destructive)
stella backup restore --id <backup-id> --confirm

# Verify restoration
stella db ping
stella db migrations status
```

### SP-004: Migration Execution

1. Pre-migration backup:
   ```bash
   stella backup create --type database --name "pre-migration"
   ```

2. Run migrations:
   ```bash
   # Dry run first
   stella db migrate --dry-run
   
   # Apply migrations
   stella db migrate
   ```

3. Verify migration success:
   ```bash
   stella db migrations status
   stella doctor --check check.postgres.migrations
   ```

---

## Incident Procedures

### INC-001: Connection Pool Exhaustion

**Symptoms:**
- Alert: `StellaPostgresPoolExhausted`
- Error logs: "connection pool exhausted, waiting for available connection"
- Increased request latency

**Investigation:**
```bash
# Check pool status
stella db pool stats

# Find long-running queries
stella db queries --active --sort duration --limit 10

# Check for connection leaks
stella db connections --by-client
```

**Resolution:**

1. **Immediate relief** - Terminate long-running queries:
   ```bash
   # Identify stuck queries
   stella db queries --active --duration ">5m"
   
   # Terminate specific query (use with caution)
   stella db query terminate --pid <pid>
   ```

2. **Scale pool** (if legitimate load):
   ```bash
   stella config set Database:MaxPoolSize 200
   stella service restart --graceful
   ```

3. **Fix leaks** (if application bug):
   - Review application logs for unclosed connections
   - Deploy fix to affected service

### INC-002: Slow Query Performance

**Symptoms:**
- Alert: `StellaPostgresQueryLatencyHigh`
- P99 query latency > 500ms

**Investigation:**
```bash
# Get slow query report
stella db queries --slow --period 1h --format json > /tmp/slow-queries.json

# Analyze specific query
stella db query explain --sql "SELECT ..." --analyze

# Check table statistics
stella db stats tables --sort bloat
```

**Resolution:**

1. **Index optimization:**
   ```bash
   # Get index recommendations
   stella db index suggest --table <table>
   
   # Create recommended index
   stella db index create --table <table> --columns "col1,col2"
   ```

2. **Vacuum/analyze:**
   ```bash
   stella db vacuum --table <table>
   stella db analyze --table <table>
   ```

3. **Query optimization** - Review and rewrite problematic queries

### INC-003: Database Connectivity Loss

**Symptoms:**
- Alert: `StellaPostgresConnectionFailed`
- All services reporting database connection errors

**Investigation:**
```bash
# Test basic connectivity
stella db ping

# Check DNS resolution
stella network dns-lookup <db-host>

# Check firewall/network
stella network test --host <db-host> --port 5432
```

**Resolution:**

1. **Network issue:**
   - Verify security groups / firewall rules
   - Check VPN/tunnel status if applicable
   - Verify DNS resolution

2. **Database server issue:**
   - Check PostgreSQL service status on server
   - Review PostgreSQL logs
   - Check disk space on database server

3. **Credential issue:**
   ```bash
   stella db verify-credentials
   stella secrets rotate --scope database
   ```

### INC-004: Disk Space Alert

**Symptoms:**
- Alert: `StellaPostgresDiskSpaceWarning` or `Critical`
- Database write failures

**Investigation:**
```bash
# Check disk usage
stella db disk-usage

# Find large tables
stella db stats tables --sort size --limit 20

# Check for bloat
stella db stats tables --sort bloat
```

**Resolution:**

1. **Immediate cleanup:**
   ```bash
   # Vacuum to reclaim space
   stella db vacuum --full --table <large-table>
   
   # Clean old data (if retention policy allows)
   stella db prune --table evidence_artifacts --older-than 90d --dry-run
   ```

2. **Archive old data:**
   ```bash
   stella db archive --table findings_history --older-than 180d
   ```

3. **Expand disk** (if legitimate growth):
   - Follow cloud provider procedure to expand volume
   - Resize filesystem

---

## Maintenance Windows

### Weekly Maintenance (Sunday 02:00 UTC)

1. Run vacuum analyze on all tables:
   ```bash
   stella db vacuum --analyze --all-tables
   ```

2. Update table statistics:
   ```bash
   stella db analyze --all-tables
   ```

3. Clean temporary files:
   ```bash
   stella db cleanup --temp-files
   ```

### Monthly Maintenance (First Sunday 03:00 UTC)

1. Full vacuum on large tables:
   ```bash
   stella db vacuum --full --table findings --table verdicts
   ```

2. Reindex if needed:
   ```bash
   stella db reindex --concurrently --table findings
   ```

3. Archive old data per retention policy:
   ```bash
   stella db archive --apply-retention
   ```

---

## Monitoring Dashboard

Access: Grafana → Dashboards → Stella Ops → PostgreSQL

Key panels:
- Connection pool utilization
- Query latency percentiles
- Disk usage trend
- Replication lag (if applicable)
- Active queries count

---

## Evidence Capture

For any incident, capture:
```bash
# Comprehensive database state
stella db diagnostics --output /tmp/db-diag-$(date +%Y%m%dT%H%M%S).tar.gz
```

Bundle includes:
- Connection stats
- Active queries
- Lock information
- Table statistics
- Recent slow query log
- Configuration snapshot

---

## Escalation Path

1. **L1 (On-call):** Standard procedures, restart services
2. **L2 (Database team):** Query optimization, schema changes
3. **L3 (Vendor support):** Hardware/cloud platform issues

---

_Last updated: 2026-01-17 (UTC)_