prax-scylladb

ScyllaDB database driver for Prax ORM - high-performance Cassandra-compatible database.

Overview

ScyllaDB is a drop-in replacement for Apache Cassandra that delivers significantly better performance through a modern C++ implementation. This crate provides async Rust support for ScyllaDB within the Prax ORM ecosystem.

Features

• High Performance: Built on the official scylla async driver
• Connection Pooling: Automatic connection management with the ScyllaDB driver's built-in pooling
• Prepared Statements: Efficient query execution with automatic caching
• Async/Await: Full async support with Tokio runtime
• Type Safety: Strong typing with automatic CQL type conversions
• Lightweight Transactions: Support for conditional updates (LWT)
• Batch Operations: Logged, unlogged, and counter batches

Installation

Add to your Cargo.toml:

[dependencies]
prax-scylladb = "0.3"
tokio = { version = "1", features = ["full"] }

Quick Start

use prax_scylladb::{ScyllaConfig, ScyllaPool, ScyllaEngine};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Connect using URL
    let pool = ScyllaPool::from_url("scylla://localhost:9042/my_keyspace").await?;

    // Or use the builder
    let config = ScyllaConfig::builder()
        .known_nodes(["node1:9042", "node2:9042", "node3:9042"])
        .default_keyspace("my_keyspace")
        .username("cassandra")
        .password("cassandra")
        .consistency(prax_scylladb::config::ConsistencyLevel::LocalQuorum)
        .build();

    let pool = ScyllaPool::connect(config).await?;

    // Create engine for queries
    let engine = pool.engine();

    // Insert data
    engine.insert(
        "users",
        &["id", "email", "name"],
        (uuid::Uuid::new_v4(), "alice@example.com", "Alice"),
    ).await?;

    // Query data
    let users: Vec<User> = engine
        .query("SELECT * FROM users WHERE email = ?", ("alice@example.com",))
        .await?;

    Ok(())
}

Configuration Options

URL Format

scylla://[user:pass@]host1:port1[,host2:port2,...]/keyspace[?options]

Options:

• timeout=30 - Request timeout in seconds
• pool_size=8 - Connections per node
• datacenter=dc1 - Preferred datacenter
• ssl=true - Enable SSL
• compression=lz4 - Enable compression
• consistency=LOCAL_QUORUM - Default consistency

Consistency Levels

Batch Operations

// Logged batch (atomic)
engine.batch()
    .logged()
    .add("INSERT INTO users (id, email) VALUES (?, ?)")
    .add("INSERT INTO user_by_email (email, id) VALUES (?, ?)")
    .execute_with_values((
        (user_id, email),
        (email, user_id),
    ))
    .await?;

// Unlogged batch (faster, non-atomic)
engine.batch()
    .unlogged()
    .add("UPDATE stats SET count = count + 1 WHERE id = ?")
    .add("UPDATE stats SET count = count + 1 WHERE id = ?")
    .execute()
    .await?;

Lightweight Transactions (LWT)

// Insert if not exists
let applied = engine.insert_if_not_exists(
    "users",
    &["id", "email"],
    (user_id, email),
).await?;

if !applied {
    println!("User already exists!");
}

// Conditional update
let applied = engine.update_if(
    "users",
    "email = ?",
    "id = ?",
    "email = ?",
    (new_email, user_id, old_email),
).await?;

Type Mapping

Features

• ssl - Enable SSL/TLS support
• cloud - Enable ScyllaDB Cloud support

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.