The Python ecosystem offers several approaches to async Cassandra connectivity. This document provides a comparison of available options to help you make an informed decision based on your specific requirements.
- Project: https://github.com/axonops/async-python-cassandra-client
- Architecture: Pure Python wrapper around the DataStax Python driver
- Language: Python
- Dependencies: cassandra-driver
Key Characteristics:
- Zero additional system dependencies
- Maintains 100% compatibility with existing DataStax driver code
- Easy migration path from sync to async code
- Stable, mature underlying driver
- No compilation or binary dependencies
Technical Approach:
- Uses thread pool for I/O (not native async)
- Bridges cassandra-driver futures to asyncio futures
- Maintains thread-based connection architecture
- Project: https://github.com/Intreecom/scyllapy
- Architecture: Rust-based driver with Python bindings
- Language: Rust core with Python interface
- Dependencies: Pre-compiled wheels or Rust toolchain for source builds
Key Characteristics:
- Native async implementation
- Built on Rust's tokio async runtime
- Includes query builder functionality
- Supports Cassandra, ScyllaDB, and AWS Keyspaces
Technical Approach:
- Implements Cassandra protocol directly in Rust
- Uses Rust's tokio async runtime for I/O
- PyO3 bindings expose Rust functionality to Python
- Project: https://github.com/acsylla/acsylla
- Architecture: C++ driver (cpp-driver) with Python bindings
- Language: C++ core with Cython wrapper
- Dependencies: Requires cassandra-cpp-driver
Key Characteristics:
- Based on DataStax C++ driver
- Supports shard-aware routing for ScyllaDB
- Comprehensive protocol support
- Available for Linux and macOS
Technical Approach:
- Uses libuv for async I/O
- Cython bindings for Python integration
- Leverages mature C++ driver codebase
- Project: Part of python-driver
- Architecture: Experimental asyncio integration in official driver
- Language: Python
- Dependencies: cassandra-driver
Key Characteristics:
- Integrated into official DataStax Python driver
- Pure Python implementation
- Marked as experimental/not production ready
Technical Approach:
- Replaces default reactor with asyncio-based implementation
- Still uses thread-based architecture internally
Note on Usage: During our evaluation, we encountered difficulties getting AsyncioReactor to establish connections successfully. This could be due to its experimental status, our specific test environment, or missing configuration requirements. Additionally, AsyncioReactor runs its event loop in a separate thread and still uses threads for I/O operations internally, which doesn't provide any performance or architectural advantages over our approach of using a thread pool executor to bridge synchronous operations to asyncio. Given its experimental designation and our connection challenges, we focused our efforts on the stable, production-ready alternatives.
| Aspect | async-python-cassandra-client | ScyllaPy | Acsylla | DataStax AsyncioReactor |
|---|---|---|---|---|
| I/O Model | Thread pool | Rust async (tokio) | C++ async (libuv) | Thread pool |
| Language Core | Python | Rust | C++ | Python |
| Binary Dependencies | None | Optional* | Required | None |
| Platform Support | All Python platforms | Windows/Linux/macOS | Linux/macOS | All Python platforms |
| Protocol Implementation | Wraps cassandra-driver | Direct in Rust | Wraps cpp-driver | Wraps cassandra-driver |
*Pre-built wheels available for common platforms
async-python-cassandra-client:
pip install async-cassandra
# No additional system dependenciesScyllaPy:
pip install scyllapy
# May require Rust toolchain for source builds
# Platform-specific wheels availableAcsylla:
# Requires cpp-driver installation first
apt-get install cassandra-cpp-driver # Ubuntu/Debian
brew install cassandra-cpp-driver # macOS
pip install acsyllaThread Pool Based (async-python-cassandra-client, DataStax AsyncioReactor):
- Wraps synchronous operations in thread pool executors
- Provides async/await syntax while maintaining thread-based I/O
- Compatible with all existing cassandra-driver features
Native Async (ScyllaPy, Acsylla):
- Implements protocol directly with async I/O primitives
- No thread pool overhead for I/O operations
- May have different feature sets from cassandra-driver
# Before (sync)
from cassandra.cluster import Cluster
cluster = Cluster(['localhost'])
session = cluster.connect()
result = session.execute("SELECT * FROM users")
# After (async)
from async_cassandra import AsyncCluster
cluster = AsyncCluster(['localhost'])
session = await cluster.connect()
result = await session.execute("SELECT * FROM users")Migration effort: Minimal - Add async/await keywords
Migration effort: Significant - Different APIs, potential feature gaps
- async-python-cassandra-client: Leverages the mature DataStax driver ecosystem
- ScyllaPy: Growing community, active development
- Acsylla: Established project with ScyllaDB focus
- DataStax AsyncioReactor: Part of official driver but experimental status
Each project maintains its own documentation. Refer to the project repositories linked above for:
- Installation guides
- API documentation
- Example code
- Issue tracking
- All libraries support basic Cassandra operations (queries, prepared statements, etc.)
- Feature parity varies for advanced functionality
- Check individual project documentation for specific feature support
- Protocol version support may differ between implementations