[xmin-sync] Task 3: Sync Command Integration (Hour 5-6)

[taariq]

Overview

Integrate all xmin modules into the sync command with automatic mode detection.

Reference

• Proposal: docs/20251208_Replication_Sync_Proposal.md

Scope

Sync Command (src/commands/sync.rs)

Add automatic wal_level detection and xmin fallback:

1. Check source wal_level
2. If 'logical' -> use existing logical replication code path
3. If 'replica' (default) -> use new xmin sync path
4. Clear INFO logging about which method is selected

Key Requirements

• Zero customer-facing flags (automatic detection)
• Clear logging of which sync method is selected
• Proper error handling and user feedback

Files to Modify

• src/commands/sync.rs
• src/lib.rs (add xmin module export)
• src/main.rs (if needed for daemon module)

Acceptance Criteria

• Auto-detects wal_level on source
• Falls back to xmin sync when wal_level != logical
• Clear INFO logging about sync method selection
• No new CLI flags required
• Integrates with existing sync command structure
• Unit tests for auto-detection logic

Important

⚠️ DO NOT fix failing tests in files outside your scope. If you encounter test failures in:

• src/xmin/reader.rs (Gemini scope)
• src/xmin/state.rs (Gemini scope)
• src/xmin/reconciler.rs (Gemini scope)
• src/daemon/* (Gemini scope)

Create a comment noting the failure but do not attempt to fix it.

Dependencies

• All previous tasks (uses all xmin modules and daemon)