PostgreSQL to Any Database Replication (pg2any)
A high-performance, production-ready PostgreSQL to Any database replication tool using Change Data Capture (CDC) with logical replication. This tool streams database changes in real-time from PostgreSQL to target databases such as MySQL and SQL Server with comprehensive error handling and monitoring.
Project Status
This is a fully functional CDC implementation providing enterprise-grade PostgreSQL to Any database replication using logical replication production-ready features.
Current Status: Production-ready CDC tool with complete PostgreSQL logical replication protocol implementation, and real-time change streaming capabilities with graceful shutdown and LSN persistence.
What's Implemented ✅
- ✅ Complete Rust Workspace: Multi-crate project with
pg2any
binary andpg2any-lib
library - ✅ Production-Ready Architecture: Async/await with Tokio, structured error handling, graceful shutdown
- ✅ PostgreSQL Logical Replication: Full protocol implementation with libpq-sys integration
- ✅ Real-time CDC Pipeline: Live streaming of INSERT, UPDATE, DELETE, TRUNCATE operations
- ✅ Transaction Consistency: BEGIN/COMMIT boundary handling with LSN persistence
- ✅ Database Destinations: Complete MySQL, SQL Server, and SQLite implementations with type mapping
- ✅ Configuration Management: Environment variables and builder pattern with validation
- ✅ Docker Development: Multi-service environment with PostgreSQL, MySQL setup
- ✅ Development Tooling: Makefile automation, formatting, linting, and quality checks
- ✅ Production Logging: Structured tracing with configurable levels and filtering
Production-Ready Features ✅
- ✅ Monitoring & Observability: Complete Prometheus metrics collection and alerting systems
- ✅ Production Logging: Structured tracing with configurable levels and HTTP metrics endpoint
- ✅ Health Monitoring: Database connection monitoring, replication lag tracking, and error rate alerts
What Needs Enhancement 🚧
- 🚧 Additional Destinations: Oracle, ClickHouse, Elasticsearch support
- 🚧 Multi-table Replication: Table filtering, routing, and transformation pipelines
- 🚧 Performance Optimization: High-throughput benchmarking and memory optimization
Features
- ✅ Async Runtime: High-performance async/await with Tokio and proper cancellation
- ✅ PostgreSQL Integration: Native logical replication with libpq-sys bindings
- ✅ Multiple Destinations: MySQL (via SQLx), SQL Server (via Tiberius), and SQLite (via SQLx) support
- ✅ Transaction Safety: ACID compliance with BEGIN/COMMIT boundary handling
- ✅ Configuration: Environment variables, builder pattern, and validation
- ✅ Error Handling: Comprehensive error types with
thiserror
and proper propagation - ✅ Real-time Streaming: Live change capture for all DML operations
- ✅ Production Ready: Structured logging, graceful shutdown, and resource management
- ✅ Monitoring & Metrics: Comprehensive Prometheus metrics, and health monitoring
- ✅ HTTP Metrics Endpoint: Built-in metrics server on port 8080 with Prometheus format
- ✅ Development Tools: Docker environment, Makefile automation, extensive testing
PostgreSQL Setup
-
Enable logical replication in your PostgreSQL configuration:
ALTER SYSTEM SET wal_level = logical; -- Restart PostgreSQL server after this change
-
Create a publication for the tables you want to replicate:
CREATE PUBLICATION my_publication FOR TABLE table1, table2; -- Or for all tables: CREATE PUBLICATION my_publication FOR ALL TABLES;
-
Create a user with replication privileges:
SELECT ON ALL TABLES IN SCHEMA public TO replicator; ;
Basic Usage
use ;
use ;
/// Main entry point for the CDC application
/// This function sets up a complete CDC pipeline from PostgreSQL to MySQL/SqlServer/SQLite
async
/// Initialize comprehensive logging configuration
///
/// Sets up structured logging with filtering, thread IDs, and ANSI colors.
/// The log level can be controlled via the `RUST_LOG` environment variable.
///
/// # Default Log Level
///
/// If `RUST_LOG` is not set, defaults to:
/// - `pg2any=debug` - Debug level for our application
/// - `tokio_postgres=info` - Info level for PostgreSQL client
/// - `sqlx=info` - Info level for SQL execution
Architecture
Core Components
- CdcClient: Main orchestrator managing the entire CDC pipeline
- Config/ConfigBuilder: Comprehensive configuration management with environment variable support
- LogicalReplicationStream: PostgreSQL logical replication lifecycle and protocol implementation
- LogicalReplicationParser: Complete PostgreSQL replication protocol message parsing
- DestinationHandler: Production-ready database destination handling (MySQL, SQL Server, SQLite)
- Error Types: Comprehensive error handling with
CdcError
and proper error propagation - Buffer Operations: Efficient binary protocol handling with zero-copy optimizations
Data Flow Architecture
PostgreSQL WAL → Logical Replication → Message Parser → Change Events → Destination Handler → Target DB
↓ ↓ ↓ ↓ ↓ ↓
Transactions Protocol Messages Parsed Events Typed Changes SQL Operations Replicated Data
Project Structure
This Cargo workspace provides a complete CDC implementation with clean separation of concerns:
pg2any/ # Workspace root
├── Cargo.toml # Workspace configuration with shared dependencies
├── Cargo.lock # Dependency lock file
├── README.md # This documentation file
├── CHANGELOG.md # Release notes and version history
├── LICENSE # Project license
├── Makefile # Development automation (35+ commands)
├── Dockerfile # Application containerization
├── docker-compose.yml # Multi-database development environment
├── .gitignore # Git ignore patterns
├── .cargo/ # Cargo configuration
├── .github/ # GitHub workflows and templates
├── .vscode/ # VS Code workspace settings
├── docs/ # Project documentation
│ └── DOCKER.md # Docker setup and usage guide
├── env/ # Environment configuration
│ ├── .env # Default environment variables
│ └── .env_local # Local development overrides
├── examples/ # Example applications and scripts
│ ├── Cargo.toml # Examples workspace configuration
│ ├── pg2any_last_lsn # LSN persistence file (runtime generated)
│ ├── src/
│ │ └── main.rs # Example CLI application entry point
│ ├── scripts/ # Database initialization scripts
│ │ ├── init_postgres.sql # PostgreSQL setup with logical replication
│ │ └── init_mysql.sql # MySQL destination database setup
│ └── monitoring/ # Monitoring and observability setup
│ ├── prometheus.yml # Prometheus configuration
│ ├── prometheus-rules/ # Alert rules for monitoring
│ │ └── cdc-alerts.yml # CDC-specific alerting rules
│ └── exporter/ # Database exporters
│ └── mysql/ # MySQL exporter configuration
├── pg2any-lib/ # Core CDC library
│ ├── Cargo.toml # Library dependencies with feature flags
│ ├── src/
│ │ ├── lib.rs # Public API exports and documentation
│ │ ├── app.rs # High-level CDC application orchestration
│ │ ├── client.rs # Main CDC client implementation
│ │ ├── config.rs # Configuration management and validation
│ │ ├── connection.rs # PostgreSQL connection handling
│ │ ├── env.rs # Environment variable loading
│ │ ├── error.rs # Comprehensive error types
│ │ ├── logical_stream.rs # Logical replication stream management
│ │ ├── pg_replication.rs # Low-level PostgreSQL replication
│ │ ├── replication_protocol.rs # Message parsing and protocol handling
│ │ ├── buffer.rs # Binary protocol buffer operations
│ │ ├── types.rs # Core data types and enums
│ │ ├── destinations/ # Database destination implementations
│ │ │ ├── mod.rs # Destination trait and factory pattern
│ │ │ ├── destination_factory.rs # Factory for creating destinations
│ │ │ ├── operation.rs # Operation types and handling
│ │ │ ├── mysql.rs # MySQL destination with SQLx
│ │ │ ├── sqlserver.rs # SQL Server destination with Tiberius
│ │ │ └── sqlite.rs # SQLite destination with SQLx
│ │ └── monitoring/ # Monitoring and metrics system
│ │ ├── mod.rs # Monitoring module exports
│ │ ├── metrics.rs # Core metrics definitions
│ │ ├── metrics_abstraction.rs # Metrics abstraction layer
│ │ └── metrics_server.rs # HTTP metrics server
│ └── tests/ # Comprehensive test suite (10 test files, 100+ tests)
│ ├── integration_tests.rs # End-to-end CDC testing
│ ├── destination_integration_tests.rs # Database destination testing
│ ├── event_type_refactor_tests.rs # Event type handling tests
│ ├── mysql_edge_cases_tests.rs # MySQL-specific edge cases
│ ├── mysql_error_handling_simple_tests.rs # Error handling tests
│ ├── mysql_where_clause_fix_tests.rs # WHERE clause generation tests
│ ├── replica_identity_tests.rs # Replica identity handling
│ ├── sqlite_comprehensive_tests.rs # SQLite comprehensive testing
│ ├── sqlite_destination_tests.rs # SQLite destination tests
│ └── where_clause_fix_tests.rs # WHERE clause bug fixes
Supported Destination Databases
Currently Implemented
- MySQL: Full implementation using SQLx with connection pooling, type mapping, and DML operations
- SQL Server: Native implementation using Tiberius TDS protocol with comprehensive type support
- SQLite: Complete implementation using SQLx with file-based storage and embedded scenarios
Change Event Types
Error Handling
The library provides comprehensive error types using thiserror
:
Configuration
pg2any supports comprehensive configuration through environment variables or the ConfigBuilder
pattern. All configuration can be managed through environment variables for containerized deployments or programmatically using the builder pattern.
Key Configuration Approach
pg2any uses CDC_DEST_URI
as the primary method for destination database configuration. This uses standard database connection string formats instead of separate host, port, user, and password variables, making configuration simpler and more portable.
# Primary configuration method (recommended)
CDC_DEST_TYPE=MySQL
CDC_DEST_URI=mysql://user:password@host:port/database
Environment Variables Mapping Table
Category | Variable | Description | Default Value | Example | Notes |
---|---|---|---|---|---|
Source PostgreSQL | |||||
CDC_SOURCE_CONNECTION_STRING |
Complete PostgreSQL connection string | postgresql://user:pass@host:port/db?replication=database |
Required for PostgreSQL logical replication | ||
Destination | |||||
CDC_DEST_TYPE |
Target database type | MySQL |
MySQL , SqlServer , SQLite |
Case-insensitive | |
CDC_DEST_URI |
Complete destination connection string | See destination-specific examples below | Primary connection method - replaces individual host/port/user/password variables | ||
CDC Settings | |||||
CDC_REPLICATION_SLOT |
PostgreSQL replication slot | cdc_slot |
my_app_slot |
||
CDC_PUBLICATION |
PostgreSQL publication name | cdc_pub |
my_app_publication |
||
CDC_PROTOCOL_VERSION |
Replication protocol version | 1 |
1 |
Integer value | |
CDC_BINARY_FORMAT |
Use binary message format | false |
true |
Boolean | |
CDC_STREAMING |
Enable streaming mode | true |
false |
Boolean | |
Timeouts | |||||
CDC_CONNECTION_TIMEOUT |
Connection timeout (seconds) | 30 |
60 |
Integer | |
CDC_QUERY_TIMEOUT |
Query timeout (seconds) | 10 |
30 |
Integer | |
CDC_HEARTBEAT_INTERVAL |
Heartbeat interval (seconds) | 10 |
15 |
Integer | |
System | |||||
CDC_LAST_LSN_FILE |
LSN persistence file | ./pg2any_last_lsn |
/data/lsn_state |
||
RUST_LOG |
Logging level | pg2any=debug,tokio_postgres=info,sqlx=info |
info |
Standard Rust logging |
Destination Database Environment Configuration
pg2any uses the CDC_DEST_URI
environment variable as the primary connection method for all destination databases. This simplifies configuration by using connection strings instead of separate host, port, user, and password variables.
MySQL Destination
# Source PostgreSQL
CDC_SOURCE_CONNECTION_STRING=postgresql://postgres:pass.123@127.0.0.1:5432/postgres?replication=database
# MySQL Destination - Complete connection string
CDC_DEST_TYPE=MySQL
CDC_DEST_URI=mysql://user:password@host:port/database
# Examples:
# Docker environment
CDC_DEST_URI=mysql://root:test.123@127.0.0.1:3306/mysql
# Production environment
CDC_DEST_URI=mysql://cdc_user:secure_pass@mysql-prod.company.com:3306/replica_db
# CDC Configuration
CDC_REPLICATION_SLOT=cdc_slot
CDC_PUBLICATION=cdc_pub
SQL Server Destination
# Source PostgreSQL
CDC_SOURCE_CONNECTION_STRING=postgresql://postgres:pass.123@127.0.0.1:5432/postgres?replication=database
# SQL Server Destination - Complete connection string
CDC_DEST_TYPE=SqlServer
CDC_DEST_URI=sqlserver://user:password@host:port/database
# Examples:
# Local SQL Server
CDC_DEST_URI=sqlserver://sa:MyPass@123@localhost:1433/master
# Azure SQL Database
CDC_DEST_URI=sqlserver://user@server:password@server.database.windows.net:1433/mydb
# Production SQL Server
CDC_DEST_URI=sqlserver://cdc_user:secure_pass@sqlserver-prod:1433/replica_db
# CDC Configuration
CDC_REPLICATION_SLOT=cdc_slot
CDC_PUBLICATION=cdc_pub
SQLite Destination
# Source PostgreSQL
CDC_SOURCE_CONNECTION_STRING=postgresql://postgres:pass.123@127.0.0.1:5432/postgres?replication=database
# SQLite Destination - File path (no authentication needed)
CDC_DEST_TYPE=SQLite
CDC_DEST_URI=./path/to/database.db
# Examples:
# Local development
CDC_DEST_URI=./my_replica.db
# Absolute path
CDC_DEST_URI=/data/cdc/replica.db
# In-memory (for testing)
CDC_DEST_URI=:memory:
# CDC Configuration
CDC_REPLICATION_SLOT=cdc_slot
CDC_PUBLICATION=cdc_pub
CDC_STREAMING=true
Connection String Format Summary
Database | CDC_DEST_URI Format | Example |
---|---|---|
MySQL | mysql://user:password@host:port/database |
mysql://root:pass123@localhost:3306/mydb |
SQL Server | sqlserver://user:password@host:port/database |
sqlserver://sa:pass123@localhost:1433/master |
SQLite | ./path/to/file.db or /absolute/path/file.db |
./replica.db or /data/replica.db |
Programmatic Configuration
You can also configure pg2any programmatically using the builder pattern with connection strings:
use ;
use Duration;
// SQLite example
let sqlite_config = builder
.source_connection_string
.destination_type
.destination_connection_string
.replication_slot_name
.publication_name
.protocol_version
.binary_format
.streaming
.build?;
// MySQL example
let mysql_config = builder
.source_connection_string
.destination_type
.destination_connection_string
.replication_slot_name
.publication_name
.connection_timeout
.query_timeout
.heartbeat_interval
.build?;
// SQL Server example
let sqlserver_config = builder
.source_connection_string
.destination_type
.destination_connection_string
.replication_slot_name
.publication_name
.build?;
Configuration Validation
The configuration system provides comprehensive validation:
- Connection Strings: Automatically formatted and validated
- Type Safety: Proper enum handling for destination types
- Default Values: Sensible defaults for all optional parameters
- Error Handling: Clear error messages for invalid configurations
Development Status
Monitoring & Observability
pg2any includes comprehensive monitoring and observability features for production environments:
Built-in Metrics System
- HTTP Metrics Endpoint: Prometheus-compatible metrics served on port 8080
- Real-time Monitoring: Replication lag, event processing rates, connection status
- Resource Tracking: Memory usage, network I/O, active connections, queue depth
Key Metrics Available
# Core Replication Metrics
pg2any_events_processed_total # Total CDC events processed
pg2any_events_by_type_total # Events by type (insert/update/delete)
pg2any_replication_lag_seconds # Current replication lag
pg2any_events_per_second # Event processing rate
pg2any_last_processed_lsn # Last processed LSN from PostgreSQL WAL
# Health & Error Metrics
pg2any_errors_total # Total errors by type and component
pg2any_source_connection_status # PostgreSQL connection status
pg2any_destination_connection_status # Destination database connection status
# Performance Metrics
pg2any_event_processing_duration_seconds # Event processing time
pg2any_queue_depth # Events waiting to be processed
pg2any_network_bytes_received_total # Network I/O from PostgreSQL
pg2any_buffer_memory_usage_bytes # Memory usage for event buffers
Complete Monitoring Stack
The Docker environment includes a full observability stack:
- Prometheus: Metrics collection and storage (port 9090)
- Node Exporter: System metrics (port 9100)
- PostgreSQL Exporter: Database metrics (port 9187)
- MySQL Exporter: Destination database metrics (port 9104)
- Alert Rules: Predefined alerts for lag, errors, and connection issues
Quick Start with Docker
Get up and running in minutes with the complete development environment including monitoring:
# Clone the repository
# Start the complete environment (databases + monitoring)
# Build the application
# Run the CDC application with monitoring
RUST_LOG=info
# Access monitoring dashboards
# In another terminal, test with sample data
Available Make Commands
Development:
Docker Management:
Local Development
For development without Docker (requires manual database setup):
# Build and validate the project
# Run the application (requires PostgreSQL and destination DB)
RUST_LOG=info
# Development workflow
Feature Configuration
pg2any supports feature flags to enable or disable optional functionality, allowing you to build a lighter binary when certain features aren't needed.
Metrics Feature
The metrics collection and HTTP metrics server can be enabled/disabled using the metrics
feature flag:
# Build with metrics (default)
# Build with metrics explicitly
# Build without metrics (smaller binary, ~17% reduction)
# Run tests with metrics enabled
Library Usage
When using pg2any as a library, you can selectively enable features:
[]
= "0.2.0"
[]
= { = "0.2.0", = false, = ["mysql"] }
[]
= { = "0.2.0", = ["metrics", "mysql", "sqlite"] }
Simple usage (metrics abstracted away):
use ;
async
With metrics server (when metrics feature enabled):
use ;
async
Example Application Output
When you run the application, you'll see structured logging output like this:
2025-08-15T10:30:00.123Z INFO pg2any: 🚀 Starting PostgreSQL CDC Application
2025-08-15T10:30:00.124Z INFO pg2any: 📋 Loading configuration from environment variables
2025-08-15T10:30:00.125Z INFO pg2any: 🔗 Configuration loaded successfully
2025-08-15T10:30:00.126Z INFO pg2any: ⚙️ Initializing CDC client
2025-08-15T10:30:00.127Z INFO pg2any: 🔧 Performing CDC client initialization
2025-08-15T10:30:00.128Z INFO pg2any: ✅ CDC client initialized successfully
2025-08-15T10:30:00.129Z INFO pg2any: 🔄 Starting CDC replication pipeline
2025-08-15T10:30:00.130Z DEBUG pg2any_lib::logical_stream: Creating logical replication stream
2025-08-15T10:30:00.131Z DEBUG pg2any_lib::pg_replication: Connected to PostgreSQL server version: 150000
2025-08-15T10:30:00.132Z INFO pg2any_lib::client: Processing BEGIN transaction (LSN: 0/1A2B3C4D)
2025-08-15T10:30:00.133Z INFO pg2any_lib::client: Processing INSERT event on table 'users'
2025-08-15T10:30:00.134Z INFO pg2any_lib::client: Processing COMMIT transaction (LSN: 0/1A2B3C5E)
2025-08-15T10:30:00.135Z INFO pg2any: ✨ CDC replication running! Real-time change streaming active
Note: This shows the production-ready application with real PostgreSQL logical replication, integrated metrics collection, LSN tracking, and comprehensive monitoring capabilities.
Dependencies
Core Runtime
- tokio (1.47.1): Async runtime with full feature set
- hyper (1.x): HTTP server for metrics endpoint
- prometheus (0.13): Metrics collection and Prometheus integration
- tokio-util (0.7.16): Utilities for async operations and cancellation
Database Clients
- sqlx (0.8.6): MySQL async client with runtime-tokio-rustls
- tiberius (0.12): Native SQL Server TDS protocol implementation
- libpq-sys (0.8): Low-level PostgreSQL C library bindings
Serialization & Data
- serde (1.0.219): Serialization framework with derive support
- serde_json (1.0.142): JSON serialization
- chrono (0.4.41): Date/time handling with serde support
- bytes (1.10.1): Byte buffer manipulation
Error Handling & Utilities
- thiserror (2.0.12): Ergonomic error handling and propagation
- async-trait (0.1.88): Async trait definitions
- tracing (0.1.41): Structured logging and instrumentation
- tracing-subscriber (0.3.20): Log filtering and formatting
- prometheus (0.13): Metrics collection library
- lazy_static (1.4): Global metrics registry initialization
- libc (0.2.174): C library bindings for system operations
Running Tests
Contributing
This project provides production-ready PostgreSQL CDC replication with a solid, well-tested foundation that makes contributing straightforward and impactful.
Getting Started Contributing
# Fork and clone the repository
# Set up development environment
# Start development databases
# Make your changes and validate
# Test end-to-end functionality
Testing Your Changes
# Manual testing with real databases
; ;
📋 Contribution Guidelines
- Code Quality: Follow existing patterns, use
make before-git-push
- Testing: Add tests for new functionality
- Documentation: Update README and inline docs
- Error Handling: Use the established
CdcError
pattern - Performance: Consider async patterns and resource usage