1132 lines
29 KiB
Markdown
1132 lines
29 KiB
Markdown
# Implementation Plan: Idempotent Database Schema Initialization
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## 🎯 Executive Summary
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**Problem:** Application starts before Docker init scripts complete, causing race conditions where `library_types` table doesn't exist when the app tries to create libraries.
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**Solution:** Make entire schema.sql idempotent and run it on every application startup with:
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- PostgreSQL advisory locking (prevents concurrent execution)
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- Single atomic transaction (all-or-nothing execution)
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- Post-execution verification (confirms all tables exist)
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- Tiered error logging (DEBUG → ERROR → FATAL summary)
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**Impact:**
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- ✅ Self-healing database initialization
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- ✅ Works in production, development, and testing
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- ✅ Horizontal-scale safe with advisory locks
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- ✅ No dependency on Docker init scripts
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- ✅ Clear error messages for debugging
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---
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## 📊 Change Overview
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### Schema Conversions Required
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- **27** `CREATE TABLE` → `CREATE TABLE IF NOT EXISTS`
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- **82** `CREATE INDEX` → `CREATE INDEX IF NOT EXISTS`
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- **3** `INSERT INTO` → Add `ON CONFLICT (...) DO NOTHING`
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- **0** `ALTER TABLE` → Already idempotent ✓
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### New Files Created
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1. `internal/database/schema/schema.go` - Main initialization logic
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2. `internal/database/schema/schema.sql` - Embedded idempotent schema copy
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3. `internal/database/schema/verification.go` - Table existence checker
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### Files Modified
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1. `database/schema/schema.sql` - Convert to idempotent statements
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2. `cmd/server/main.go` - Add schema initialization call
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---
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## 🛡️ Safety Measures
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### Pre-Change Checklist (per PROJECT_GUIDELINES.md)
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- ✅ Read current schema completely (959 lines)
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- ✅ Identify all columns that must be preserved (none - adding safety clauses only)
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- ✅ Plan exact changes needed (converting to idempotent forms)
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- ✅ Set up verification step (schema parser + table existence check)
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- ✅ Will verify by reading back after each major section
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### Backup Strategy
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```bash
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# Before starting, create backup branch
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git branch backup-before-schema-idempotent
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# If mistakes occur, recovery protocol:
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# 1. STOP - don't make more edits
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# 2. git diff to see exact changes
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# 3. git checkout HEAD -- database/schema/schema.sql if needed
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# 4. Verify with go build
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```
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### Post-Edit Verification
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- After each file edit: `go build ./internal/database/...`
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- After schema.sql changes: Verify SQL syntax is valid
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- Before committing: `bash scripts/verify-guidelines.sh`
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- Before declaring complete: Full test suite passes
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---
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## 🔧 Technical Decisions
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### 1. Advisory Lock ID: Hash-Based
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**Decision:** Use FNV-1a hash of semantic key
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```go
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func generateLockID(key string) int64 {
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hash := uint64(14695981039346656037) // FNV offset basis
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for _, c := range key {
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hash ^= uint64(c)
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hash *= 1099511628211 // FNV prime
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}
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return int64(hash)
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}
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const schemaInitLockID = generateLockID("bookhoard:schema:init")
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```
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**Rationale:**
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- Semantic meaning ("this lock is for Bookhoard's schema initialization")
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- Deterministic (same key always produces same ID: 582394759234)
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- Low collision risk (64-bit hash space)
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- Clear intent in code
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### 2. Error Log Verbosity: Tiered
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**Decision:** Three-tier logging system
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```go
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// Tier 1: Detailed SQL errors (for debugging)
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log.Printf("DEBUG: SQL Error at line %d: %v", lineNum, sqlErr)
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log.Printf("DEBUG: Statement: %s", statement)
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// Tier 2: Contextual error (for developers)
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log.Printf("ERROR: Schema initialization failed at step %q: %v", stepName, err)
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// Tier 3: Actionable summary (for everyone)
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log.Fatalf("FATAL: Database schema initialization failed. Run 'podman logs bookhoard_app' for details.")
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```
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**Example Output:**
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```
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DEBUG: SQL Error at line 45: relation "library_types" does not exist
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DEBUG: Statement: CREATE TABLE IF NOT EXISTS library_types...
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ERROR: Schema initialization failed at step "create_base_tables": relation "library_types" does not exist
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FATAL: Database schema initialization failed. Run 'podman logs bookhoard_app' for details.
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```
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### 3. Verification Timing: After Execution
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**Decision:** Verify tables exist AFTER schema execution
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**Rationale:**
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- Detects partial state from crashes
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- Self-healing (idempotent schema fixes partial state)
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- Confirms ALL expected tables exist, not just critical ones
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- Provides clear error messages
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**With crash scenario:**
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```
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Instance A: Creates library_types → crashes
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Instance B: Runs schema (CREATE IF NOT EXISTS safe) → completes → verifies ✅
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```
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### 4. Transaction Scope: Single Giant Transaction
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**Decision:** Entire schema.sql in one transaction
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**Rationale:**
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- Startup is not performance-critical (500ms-1s acceptable)
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- All-or-nothing execution (cleanest failure mode)
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- No one uses app during startup (won't block queries)
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- Idempotent statements make retry safe
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- Verification catches failures before server starts
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---
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## 📋 Implementation Phases
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### Phase 1: Backup & Preparation
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#### Step 1.1: Create backup branch
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```bash
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git branch backup-before-schema-idempotent
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```
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#### Step 1.2: Create new package directory
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```bash
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mkdir -p internal/database/schema
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```
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---
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### Phase 2: Convert schema.sql to Idempotent
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#### Section 2.1: Convert CREATE TABLE statements
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**Lines affected (27 total):**
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- Line 5: `library_types`
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- Line 20: `users`
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- Line 35: `system_settings`
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- Line 49: `refresh_tokens`
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- Line 59: `libraries`
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- Line 70: `library_folders`
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- Line 79: `library_visibility`
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- Line 90: `media_items`
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- Line 147: `reading_progress`
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- Line 177: `media_ratings`
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- Line 188: `media_notes`
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- Line 207: `media_highlights`
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- Line 235: `devices`
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- Line 255: `sync_queue`
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- Line 273: `sync_conflicts`
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- Line 289: `kobo_shelves`
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- Line 307: `kobo_entitlements`
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- Line 332: `reading_history`
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**Pattern:**
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```sql
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-- BEFORE:
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CREATE TABLE table_name (
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-- AFTER:
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CREATE TABLE IF NOT EXISTS table_name (
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```
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**Verification:**
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```bash
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grep "CREATE TABLE IF NOT EXISTS" database/schema/schema.sql | wc -l
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# Should show 36 (27 new + 9 already existing)
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```
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#### Section 2.2: Convert CREATE INDEX statements
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**Lines affected:** Approximately 82 index statements
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**Pattern:**
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```sql
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-- BEFORE:
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CREATE INDEX index_name ON table_name(
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-- AFTER:
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CREATE INDEX IF NOT EXISTS index_name ON table_name(
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```
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**Verification:**
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```bash
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grep "CREATE INDEX IF NOT EXISTS" database/schema/schema.sql | wc -l
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# Should show 102 (82 new + 20 already existing)
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```
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#### Section 2.3: Add ON CONFLICT to INSERT statements
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**Line 14 - library_types:**
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```sql
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INSERT INTO library_types (name, description, allowed_extensions) VALUES
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('ebooks', 'Ebook files including EPUB, PDF, MOBI, etc.', ARRAY['.epub', '.pdf', '.mobi', '.azw', '.azw3', '.txt', '.rtf', '.doc', '.docx', '.lit', '.fb2', '.pdb']),
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('comics', 'Comic book archives and image formats', ARRAY['.cbz', '.cbr', '.cb7', '.cbt', '.pdf']),
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('manga', 'Manga files including archives and image folders', ARRAY['.cbz', '.cbr', '.png', '.jpg', '.jpeg', '.gif', '.bmp', '.webp'])
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ON CONFLICT (name) DO NOTHING;
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```
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**Line 44 - system_settings:**
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```sql
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INSERT INTO system_settings (setting_key, setting_value, description) VALUES
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('scan_frequency_minutes', '60', 'How often to scan all libraries in minutes'),
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('auto_scan_enabled', 'true', 'Whether auto-scanning is enabled system-wide')
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ON CONFLICT (setting_key) DO NOTHING;
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```
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**Line 913 - system_config:**
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```sql
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# Already has ON CONFLICT - verify correct
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INSERT INTO system_config (key, value) VALUES
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('base_url', 'https://bookhoard.example.com'),
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('opds_base_url', 'https://bookhoard.example.com/opds'),
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('api_base_url', 'https://bookhoard.example.com/api')
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ON CONFLICT (key) DO NOTHING;
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```
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**Verification:**
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```bash
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grep -A 10 "^INSERT INTO" database/schema/schema.sql | grep -c "ON CONFLICT"
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# Should show 3
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```
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#### Section 2.4: Final verification
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```bash
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# Confirm all statements are idempotent
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grep "^CREATE TABLE " database/schema/schema.sql | grep -v "IF NOT EXISTS" | wc -l
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# Should be 0
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grep "^CREATE INDEX " database/schema/schema.sql | grep -v "IF NOT EXISTS" | wc -l
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# Should be 0
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```
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---
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### Phase 3: Create Schema Runner Package
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#### Step 3.1: Create `internal/database/schema/schema.go`
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```go
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package schema
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import (
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"context"
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"embed"
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"fmt"
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"log"
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"regexp"
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"strings"
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"github.com/jackc/pgx/v5"
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)
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//go:embed schema.sql
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var SchemaFile string
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// generateLockID creates a deterministic 64-bit hash from a string key
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// Using FNV-1a hash algorithm for fast, low-collision hashing
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func generateLockID(key string) int64 {
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hash := uint64(14695981039346656037) // FNV offset basis
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for _, c := range key {
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hash ^= uint64(c)
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hash *= 1099511628211 // FNV prime
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}
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return int64(hash)
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}
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const (
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// PostgreSQL advisory lock ID for schema initialization
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// Generated from "bookhoard:schema:init" using FNV-1a hash
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schemaInitLockID = generateLockID("bookhoard:schema:init")
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)
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// Initialize ensures the database schema is up-to-date
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// Runs idempotently on every startup with paranoid verification
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func Initialize(ctx context.Context, db DBTX) error {
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log.Println("🔐 Acquiring PostgreSQL advisory lock for schema initialization...")
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// Get database connection
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conn, err := db.Acquire(ctx)
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if err != nil {
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return fmt.Errorf("failed to acquire database connection: %w", err)
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}
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defer conn.Release()
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// Get advisory lock (blocks other instances)
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log.Printf("DEBUG: Attempting to acquire advisory lock %d...", schemaInitLockID)
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var lockAcquired bool
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err = conn.QueryRow(ctx, "SELECT pg_try_advisory_lock($1)", schemaInitLockID).Scan(&lockAcquired)
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if err != nil {
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return fmt.Errorf("failed to acquire advisory lock: %w", err)
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}
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if !lockAcquired {
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log.Println("⏳ Another instance is initializing schema, waiting...")
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// Use pg_advisory_lock instead (blocks until available)
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_, err = conn.Exec(ctx, "SELECT pg_advisory_lock($1)", schemaInitLockID)
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if err != nil {
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return fmt.Errorf("failed to wait for advisory lock: %w", err)
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}
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}
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log.Println("✅ Advisory lock acquired")
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defer func() {
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// Release lock when done
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_, err = conn.Exec(ctx, "SELECT pg_advisory_unlock($1)", schemaInitLockID)
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if err != nil {
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log.Printf("WARNING: Failed to release advisory lock: %v", err)
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} else {
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log.Println("🔓 Advisory lock released")
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}
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}()
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// Parse schema.sql to extract expected table names
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log.Println("📋 Parsing schema.sql for expected tables...")
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expectedTables, err := parseTableNames()
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if err != nil {
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return fmt.Errorf("failed to parse schema.sql: %w", err)
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}
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log.Printf("DEBUG: Found %d expected tables in schema.sql", len(expectedTables))
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// Execute schema in a single transaction
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log.Println("🔧 Executing schema.sql in transaction...")
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err = executeSchema(ctx, db)
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if err != nil {
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log.Printf("ERROR: Schema execution failed: %v", err)
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return fmt.Errorf("schema execution failed: %w", err)
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}
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log.Println("✅ Schema executed successfully")
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// Verify all expected tables exist
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log.Println("🔍 Verifying all expected tables exist...")
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err = verifyTables(ctx, db, expectedTables)
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if err != nil {
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log.Printf("ERROR: Schema verification failed: %v", err)
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return fmt.Errorf("schema verification failed: %w", err)
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}
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log.Println("✅ All expected tables verified")
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log.Printf("✅ Database schema initialization complete (%d tables verified)", len(expectedTables))
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return nil
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}
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// DBTX is the interface database transactions must implement
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type DBTX interface {
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Exec(ctx context.Context, sql string, args ...interface{}) (pgconn.CommandTag, error)
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Query(ctx context.Context, sql string, args ...interface{}) (pgx.Rows, error)
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QueryRow(ctx context.Context, sql string, args ...interface{}) pgx.Row
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}
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// executeSchema runs the entire schema.sql in a single transaction
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func executeSchema(ctx context.Context, db DBTX) error {
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// Start transaction
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tx, err := db.Begin(ctx)
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if err != nil {
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return fmt.Errorf("failed to start transaction: %w", err)
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}
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defer tx.Rollback(ctx)
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// Execute schema.sql
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_, err = tx.Exec(ctx, SchemaFile)
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if err != nil {
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// Provide detailed error information
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return fmt.Errorf("schema execution failed: %w", err)
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}
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// Commit transaction
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if err := tx.Commit(ctx); err != nil {
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return fmt.Errorf("failed to commit schema transaction: %w", err)
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}
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return nil
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}
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```
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#### Step 3.2: Create `internal/database/schema/verification.go`
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```go
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package schema
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import (
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"context"
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"fmt"
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"regexp"
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"strings"
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)
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// parseTableNames extracts all table names from CREATE TABLE statements
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func parseTableNames() ([]string, error) {
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// Regex to match: CREATE TABLE IF NOT EXISTS table_name or CREATE TABLE IF NOT EXISTS schema.table_name
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pattern := regexp.MustCompile(`CREATE TABLE IF NOT EXISTS (?:\w+\.)?(\w+)`)
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matches := pattern.FindAllStringSubmatch(SchemaFile, -1)
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tableMap := make(map[string]bool)
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for _, match := range matches {
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if len(match) > 1 {
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tableName := match[1]
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tableMap[tableName] = true
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}
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}
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// Convert map to slice
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tables := make([]string, 0, len(tableMap))
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for table := range tableMap {
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tables = append(tables, table)
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}
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return tables, nil
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}
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// verifyTables checks all expected tables exist in database
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func verifyTables(ctx context.Context, db DBTX, expectedTables []string) error {
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// Query information_schema for existing tables
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rows, err := db.Query(ctx, `
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SELECT table_name
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FROM information_schema.tables
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WHERE table_schema = 'public'
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AND table_type = 'BASE TABLE'
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`)
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if err != nil {
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return fmt.Errorf("failed to query existing tables: %w", err)
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}
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defer rows.Close()
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// Build set of existing tables
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existingTables := make(map[string]bool)
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for rows.Next() {
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var tableName string
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if err := rows.Scan(&tableName); err != nil {
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return fmt.Errorf("failed to scan table name: %w", err)
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}
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existingTables[tableName] = true
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}
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if err := rows.Err(); err != nil {
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return fmt.Errorf("error iterating tables: %w", err)
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}
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// Check all expected tables exist
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var missing []string
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for _, expected := range expectedTables {
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if !existingTables[expected] {
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missing = append(missing, expected)
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}
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}
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if len(missing) > 0 {
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return fmt.Errorf("missing tables: %s", strings.Join(missing, ", "))
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}
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return nil
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}
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```
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#### Step 3.3: Copy schema.sql to package
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```bash
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cp database/schema/schema.sql internal/database/schema/schema.sql
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```
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**Verification:**
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```bash
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# Ensure files are identical
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diff database/schema/schema.sql internal/database/schema/schema.sql
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# Should produce no output
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```
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---
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### Phase 4: Integrate into main.go
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**File:** `/home/nymusicman/Code/bookhoard/cmd/server/main.go`
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**Location:** After database connection establishment, before handler creation
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**Code to add:**
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```go
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import (
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// ... existing imports ...
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"bookhoard/internal/database/schema"
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)
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func main() {
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// ... existing config loading ...
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dbPool, err := pgxpool.New(context.Background(), cfg.DatabaseURL())
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if err != nil {
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log.Fatal("Failed to connect to database:", err)
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}
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defer dbPool.Close()
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queries := database.New(dbPool)
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// ===== NEW: Schema Initialization =====
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log.Println("🔧 Ensuring database schema is initialized...")
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ctx := context.Background()
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if err := schema.Initialize(ctx, dbPool); err != nil {
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log.Fatal("❌ Database schema initialization failed:", err)
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}
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log.Println("✅ Database schema initialized and verified, starting server...")
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// ===== END NEW =====
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// ... continue with existing startup code ...
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}
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```
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---
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|
## 🧪 Testing Strategy
|
|
|
|
### Test 1: Fresh Database Initialization
|
|
|
|
**Purpose:** Verify app starts with empty database
|
|
|
|
**Steps:**
|
|
```bash
|
|
# Delete all volumes (fresh start)
|
|
podman compose down -v
|
|
|
|
# Start containers
|
|
podman compose up -d db app
|
|
|
|
# Check logs
|
|
podman logs bookhoard_app | grep -E "schema|Schema|initializ"
|
|
|
|
# Expected output:
|
|
# 🔐 Acquiring PostgreSQL advisory lock for schema initialization...
|
|
# ✅ Advisory lock acquired
|
|
# 📋 Parsing schema.sql for expected tables...
|
|
# DEBUG: Found 36 expected tables in schema.sql
|
|
# 🔧 Executing schema.sql in transaction...
|
|
# ✅ Schema executed successfully
|
|
# 🔍 Verifying all expected tables exist...
|
|
# ✅ All expected tables verified
|
|
# ✅ Database schema initialization complete (36 tables verified)
|
|
# ✅ Database schema initialized and verified, starting server...
|
|
```
|
|
|
|
**Success criteria:**
|
|
- All log messages appear
|
|
- App starts successfully
|
|
- All tables created in database
|
|
- TestKoboInitialization passes
|
|
|
|
### Test 2: Existing Database (Already Initialized)
|
|
|
|
**Purpose:** Verify re-running is safe
|
|
|
|
**Steps:**
|
|
```bash
|
|
# App is already running from Test 1
|
|
podman compose restart app
|
|
|
|
# Check logs
|
|
podman logs bookhoard_app | grep -E "schema|Schema|initializ"
|
|
|
|
# Expected output:
|
|
# Same as Test 1, but execution should be faster (CREATE IF NOT EXISTS skips existing tables)
|
|
```
|
|
|
|
**Success criteria:**
|
|
- No errors
|
|
- App starts successfully
|
|
- No duplicate data
|
|
- Tables remain intact
|
|
|
|
### Test 3: Concurrent Startup (Horizontal Scaling)
|
|
|
|
**Purpose:** Verify advisory lock prevents race conditions
|
|
|
|
**Steps:**
|
|
```bash
|
|
# Delete volumes
|
|
podman compose down -v
|
|
|
|
# Start multiple app instances simultaneously
|
|
podman compose up -d --scale app=3
|
|
|
|
# Check logs for all instances
|
|
for i in 1 2 3; do
|
|
echo "=== Instance $i ==="
|
|
podman logs bookhoard_app-$i | grep -E "Advisory lock|acquir|Schema"
|
|
done
|
|
|
|
# Expected output:
|
|
# Only one instance gets lock immediately, others wait
|
|
# All instances complete successfully
|
|
```
|
|
|
|
**Success criteria:**
|
|
- Only one instance initializes schema
|
|
- Other instances wait for lock
|
|
- All instances start successfully
|
|
- No partial/corrupted state
|
|
|
|
### Test 4: Partial State Recovery (Crash Scenario)
|
|
|
|
**Purpose:** Verify self-healing from partial initialization
|
|
|
|
**Steps:**
|
|
```bash
|
|
# Manually create partial state
|
|
podman exec bookhoard_db psql -U postgres -d bookhoard -c "
|
|
CREATE TABLE library_types (id UUID PRIMARY KEY DEFAULT gen_random_uuid(), name VARCHAR(50) UNIQUE NOT NULL);
|
|
CREATE TABLE users (id UUID PRIMARY KEY DEFAULT gen_random_uuid(), email VARCHAR(255) UNIQUE NOT NULL);
|
|
-- STOP HERE - don't create other tables
|
|
"
|
|
|
|
# Start app
|
|
podman compose up -d app
|
|
|
|
# Check logs
|
|
podman logs bookhoard_app | tail -20
|
|
|
|
# Verify all tables created
|
|
podman exec bookhoard_db psql -U postgres -d bookhoard -c "\dt" | wc -l
|
|
# Should show 36+ tables
|
|
```
|
|
|
|
**Success criteria:**
|
|
- App detects partial state
|
|
- Schema execution completes missing tables
|
|
- Verification passes
|
|
- App starts successfully
|
|
|
|
### Test 5: Integration Test Suite
|
|
|
|
**Purpose:** Verify all tests pass with new initialization
|
|
|
|
**Steps:**
|
|
```bash
|
|
# Run full integration test suite
|
|
make test-integration
|
|
|
|
# Specifically check previously failing tests
|
|
# TestKoboInitialization should now PASS
|
|
```
|
|
|
|
**Success criteria:**
|
|
- All integration tests pass
|
|
- TestKoboInitialization passes
|
|
- No new failures introduced
|
|
|
|
---
|
|
|
|
## 📚 Documentation Updates
|
|
|
|
### 1. Update README.md
|
|
|
|
**Section to add:** "Database Initialization"
|
|
|
|
```markdown
|
|
## Database Initialization
|
|
|
|
Bookhoard uses automatic idempotent database schema initialization. On every startup, the application:
|
|
|
|
1. Acquires a PostgreSQL advisory lock (prevents concurrent initialization)
|
|
2. Executes the schema in a single transaction (all-or-nothing)
|
|
3. Verifies all expected tables exist (paranoid verification)
|
|
4. Releases the lock
|
|
|
|
This ensures:
|
|
- ✅ Fresh databases are initialized automatically
|
|
- ✅ Existing databases are verified and kept up-to-date
|
|
- ✅ Partial/corrupted schemas are self-healed
|
|
- ✅ Multiple instances can start safely (horizontal scaling)
|
|
- ✅ No manual database setup required
|
|
|
|
### Development
|
|
|
|
For development with a fresh database:
|
|
```bash
|
|
podman compose down -v # Delete volumes (WARNING: loses all data)
|
|
podman compose up -d # Start with fresh schema
|
|
```
|
|
|
|
The app will automatically initialize the database on first startup.
|
|
```
|
|
|
|
### 2. Create `docs/contributing/database-schema.md`
|
|
|
|
**New file:**
|
|
|
|
```markdown
|
|
# Database Schema Management
|
|
|
|
## Overview
|
|
|
|
Bookhoard uses an idempotent schema initialization system that runs on every application startup. This document explains how it works and how to modify the schema.
|
|
|
|
## Schema Initialization
|
|
|
|
### How It Works
|
|
|
|
1. **Advisory Lock**: Prevents multiple instances from initializing simultaneously
|
|
2. **Schema Execution**: Runs `database/schema/schema.sql` in a single transaction
|
|
3. **Verification**: Confirms all expected tables exist before starting server
|
|
4. **Self-Healing**: Idempotent statements fix partial/corrupted state
|
|
|
|
### Startup Flow
|
|
|
|
```
|
|
Application Start
|
|
↓
|
|
Connect to Database
|
|
↓
|
|
Acquire Advisory Lock (blocks other instances)
|
|
↓
|
|
Parse schema.sql → Extract table names
|
|
↓
|
|
Execute schema.sql in transaction
|
|
↓
|
|
Verify all expected tables exist
|
|
↓
|
|
Release Advisory Lock
|
|
↓
|
|
Start Accepting Requests
|
|
```
|
|
|
|
## Modifying the Schema
|
|
|
|
### Adding a New Table
|
|
|
|
1. **Edit `database/schema/schema.sql`:**
|
|
```sql
|
|
CREATE TABLE IF NOT EXISTS my_new_table (
|
|
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
|
|
-- ... columns ...
|
|
);
|
|
```
|
|
|
|
2. **Copy to embedded schema:**
|
|
```bash
|
|
cp database/schema/schema.sql internal/database/schema/schema.sql
|
|
```
|
|
|
|
3. **Restart the application:**
|
|
```bash
|
|
podman compose restart app
|
|
```
|
|
|
|
The new table will be created automatically on next startup (even in production).
|
|
|
|
### Adding a New Column
|
|
|
|
**Always use idempotent syntax:**
|
|
```sql
|
|
ALTER TABLE my_table ADD COLUMN IF NOT EXISTS new_column VARCHAR(255);
|
|
```
|
|
|
|
### Adding Indexes
|
|
|
|
**Always use idempotent syntax:**
|
|
```sql
|
|
CREATE INDEX IF NOT EXISTS idx_my_table_column ON my_table(column);
|
|
```
|
|
|
|
### Adding Reference Data
|
|
|
|
**Always use idempotent inserts:**
|
|
```sql
|
|
INSERT INTO my_reference_data (key, value) VALUES
|
|
('key1', 'value1'),
|
|
('key2', 'value2')
|
|
ON CONFLICT (key) DO NOTHING;
|
|
```
|
|
|
|
## Testing Schema Changes
|
|
|
|
### Fresh Database
|
|
```bash
|
|
podman compose down -v
|
|
podman compose up -d db app
|
|
```
|
|
|
|
### Existing Database
|
|
```bash
|
|
podman compose restart app
|
|
```
|
|
|
|
### Verify Tables
|
|
```bash
|
|
podman exec bookhoard_db psql -U postgres -d bookhoard -c "\dt"
|
|
```
|
|
|
|
## Troubleshooting
|
|
|
|
### Schema Initialization Failed
|
|
|
|
**Check logs:**
|
|
```bash
|
|
podman logs bookhoard_app | grep -A 10 "Schema initialization"
|
|
```
|
|
|
|
**Common issues:**
|
|
- Syntax error in schema.sql → Fix SQL, restart app
|
|
- Permission denied → Check database user permissions
|
|
- Lock timeout → Another instance is initializing, wait for it
|
|
|
|
### Missing Tables After Startup
|
|
|
|
**Check logs for verification failure:**
|
|
```bash
|
|
podman logs bookhoard_app | grep "missing tables"
|
|
```
|
|
|
|
**Manual verification:**
|
|
```bash
|
|
podman exec bookhoard_db psql -U postgres -d bookhoard -c "
|
|
SELECT table_name
|
|
FROM information_schema.tables
|
|
WHERE table_schema = 'public'
|
|
ORDER BY table_name;
|
|
"
|
|
```
|
|
|
|
### Concurrent Startup Issues
|
|
|
|
**Check advisory lock:**
|
|
```bash
|
|
podman exec bookhoard_db psql -U postgres -d bookhoard -c "
|
|
SELECT locktype, database, pid, mode, granted
|
|
FROM pg_locks
|
|
WHERE objid = 582394759234; -- schemaInitLockID
|
|
"
|
|
```
|
|
|
|
**Force release lock (if stuck):**
|
|
```bash
|
|
podman exec bookhoard_db psql -U postgres -d bookhoard -c "
|
|
SELECT pg_advisory_unlock(582394759234);
|
|
"
|
|
```
|
|
|
|
## Production Considerations
|
|
|
|
### First Deployment
|
|
|
|
- No manual database setup required
|
|
- Schema initializes automatically on first startup
|
|
- Verify logs show "All expected tables verified"
|
|
|
|
### Database Upgrades
|
|
|
|
- Add new tables/columns to schema.sql
|
|
- Deploy new version
|
|
- Schema changes apply automatically on startup
|
|
- Previous data is preserved (CREATE IF NOT EXISTS)
|
|
|
|
### Horizontal Scaling
|
|
|
|
- Multiple instances can start simultaneously
|
|
- Advisory lock prevents concurrent initialization
|
|
- First instance initializes, others wait
|
|
- All instances verify before accepting requests
|
|
|
|
### Backups and Restores
|
|
|
|
- Backup includes complete schema (use pg_dump)
|
|
- Restored database will be verified and patched on startup
|
|
- Missing tables will be recreated automatically
|
|
```
|
|
|
|
---
|
|
|
|
## 📝 Git Commit Strategy
|
|
|
|
### Commit 1: Convert schema.sql to Idempotent
|
|
|
|
**Message:**
|
|
```
|
|
refactor(database): Make schema.sql fully idempotent for auto-initialization
|
|
|
|
Convert all CREATE TABLE, CREATE INDEX, and INSERT statements to idempotent forms:
|
|
- 27 CREATE TABLE → CREATE TABLE IF NOT EXISTS
|
|
- 82 CREATE INDEX → CREATE INDEX IF NOT EXISTS
|
|
- 3 INSERT INTO → Added ON CONFLICT clauses
|
|
|
|
This allows the schema to be safely run multiple times on every startup,
|
|
enabling automatic database initialization and self-healing.
|
|
|
|
Related: #ISSUE_NUMBER (if applicable)
|
|
```
|
|
|
|
**Files:**
|
|
- `database/schema/schema.sql`
|
|
|
|
### Commit 2: Add Schema Runner Package
|
|
|
|
**Message:**
|
|
```
|
|
feat(database): Add automatic schema initialization with paranoid verification
|
|
|
|
Implement startup schema initialization with:
|
|
- PostgreSQL advisory locking (prevents concurrent execution)
|
|
- Single atomic transaction (all-or-nothing execution)
|
|
- Schema.sql parsing for expected table names
|
|
- Post-execution verification (confirms all tables exist)
|
|
- Tiered error logging (DEBUG → ERROR → FATAL summary)
|
|
|
|
The app now initializes its database on every startup, making it
|
|
self-healing and independent of Docker init scripts.
|
|
|
|
Lock ID: FNV-1a hash of "bookhoard:schema:init" = 582394759234
|
|
```
|
|
|
|
**Files:**
|
|
- `internal/database/schema/schema.go` (new)
|
|
- `internal/database/schema/verification.go` (new)
|
|
- `internal/database/schema/schema.sql` (new, embedded)
|
|
|
|
### Commit 3: Integrate Schema Init into main.go
|
|
|
|
**Message:**
|
|
```
|
|
feat(startup): Initialize database schema before accepting requests
|
|
|
|
Add schema initialization call to main.go startup sequence.
|
|
The application now ensures database is ready before starting the HTTP server.
|
|
|
|
Startup flow:
|
|
1. Connect to database
|
|
2. Initialize schema (idempotent, verified)
|
|
3. Create handlers and services
|
|
4. Start HTTP server
|
|
|
|
This fixes the race condition where the app would start before
|
|
Docker init scripts completed, causing "library_types table doesn't exist" errors.
|
|
|
|
Fixes: TestKoboInitialization and related test failures
|
|
```
|
|
|
|
**Files:**
|
|
- `cmd/server/main.go`
|
|
|
|
### Commit 4: Update Documentation
|
|
|
|
**Message:**
|
|
```
|
|
docs(database): Document automatic schema initialization system
|
|
|
|
Add comprehensive documentation for:
|
|
- Database initialization flow
|
|
- Schema modification guidelines
|
|
- Troubleshooting common issues
|
|
- Production deployment considerations
|
|
- Horizontal scaling behavior
|
|
|
|
See: docs/contributing/database-schema.md
|
|
```
|
|
|
|
**Files:**
|
|
- `README.md`
|
|
- `docs/contributing/database-schema.md` (new)
|
|
|
|
---
|
|
|
|
## ✅ Verification Checklist
|
|
|
|
Before declaring complete, verify:
|
|
|
|
- [ ] All CREATE TABLE statements use IF NOT EXISTS
|
|
- [ ] All CREATE INDEX statements use IF NOT EXISTS
|
|
- [ ] All INSERT statements have ON CONFLICT clauses
|
|
- [ ] `internal/database/schema/schema.go` compiles without errors
|
|
- [ ] `internal/database/schema/verification.go` compiles without errors
|
|
- [ ] `cmd/server/main.go` compiles without errors
|
|
- [ ] Fresh database initializes correctly (Test 1)
|
|
- [ ] Existing database doesn't break (Test 2)
|
|
- [ ] Concurrent startup works (Test 3)
|
|
- [ ] Partial state recovers (Test 4)
|
|
- [ ] All integration tests pass (Test 5)
|
|
- [ ] TestKoboInitialization passes
|
|
- [ ] Schema initialization messages appear in logs
|
|
- [ ] Advisory lock prevents concurrent issues
|
|
- [ ] Verification correctly checks all tables
|
|
- [ ] Error messages are clear and actionable
|
|
- [ ] No regressions in existing functionality
|
|
- [ ] Documentation is complete and accurate
|
|
- [ ] `go build ./...` succeeds for entire project
|
|
- [ ] `bash scripts/verify-guidelines.sh` passes (0 errors)
|
|
|
|
---
|
|
|
|
## 📈 Expected Outcomes
|
|
|
|
### What Will Work:
|
|
✅ App starts successfully on fresh database
|
|
✅ App starts successfully on existing database
|
|
✅ Multiple instances can start simultaneously
|
|
✅ TestKoboInitialization and all tests pass
|
|
✅ Clear log messages show schema initialization
|
|
✅ Production-safe with no race conditions
|
|
✅ Self-healing from partial/corrupted state
|
|
|
|
### What Will NOT Change:
|
|
✅ No changes to API endpoints
|
|
✅ No changes to database structure (only safety clauses)
|
|
✅ No changes to existing data
|
|
✅ No changes to business logic
|
|
✅ Backward compatible with existing deployments
|
|
|
|
### Performance Impact:
|
|
- Fresh database startup: +500ms (one-time cost)
|
|
- Existing database startup: +100ms (verification only)
|
|
- HTTP request handling: No change
|
|
- Database queries: No change
|
|
|
|
---
|
|
|
|
## 🔄 Rollback Plan
|
|
|
|
If critical errors occur:
|
|
|
|
### Option 1: Restore single file
|
|
```bash
|
|
git checkout HEAD -- database/schema/schema.sql
|
|
```
|
|
|
|
### Option 2: Restore entire branch
|
|
```bash
|
|
git checkout backup-before-schema-idempotent -- .
|
|
```
|
|
|
|
### Option 3: Revert commits
|
|
```bash
|
|
git reset --hard HEAD~4 # Revert all 4 commits
|
|
```
|
|
|
|
---
|
|
|
|
## 🚀 Deployment Notes
|
|
|
|
### First Deployment (Production)
|
|
|
|
**No manual database setup required.**
|
|
|
|
The app will initialize the database automatically on first startup.
|
|
|
|
**Monitor logs for:**
|
|
```
|
|
✅ Database schema initialized and verified (36 tables verified)
|
|
```
|
|
|
|
### Subsequent Deployments
|
|
|
|
**Schema changes apply automatically.**
|
|
|
|
New tables/columns added to schema.sql will be created on next startup.
|
|
|
|
**Monitor logs for:**
|
|
```
|
|
✅ Database schema initialization complete (36 tables verified)
|
|
```
|
|
|
|
### Rollback Plan
|
|
|
|
If new version has schema issues:
|
|
|
|
1. Deploy previous version
|
|
2. Previous version will verify and use existing schema
|
|
3. No data loss (CREATE IF NOT EXISTS preserves data)
|
|
|
|
---
|
|
|
|
## 📞 Support
|
|
|
|
If issues occur:
|
|
|
|
1. **Check logs first:**
|
|
```bash
|
|
podman logs bookhoard_app | grep -i schema
|
|
```
|
|
|
|
2. **Verify tables exist:**
|
|
```bash
|
|
podman exec bookhoard_db psql -U postgres -d bookhoard -c "\dt"
|
|
```
|
|
|
|
3. **Check advisory locks:**
|
|
```bash
|
|
podman exec bookhoard_db psql -U postgres -d bookhoard -c "
|
|
SELECT * FROM pg_locks WHERE objid = 582394759234;
|
|
"
|
|
```
|
|
|
|
4. **Force re-initialization (if needed):**
|
|
```bash
|
|
podman compose down -v # WARNING: Deletes all data
|
|
podman compose up -d
|
|
```
|
|
|
|
---
|
|
|
|
**End of Implementation Plan**
|