SIMD R Drive Extensions

Work in progress.

simd-r-drive-extensions provides optional utilities for working with Option<T> and TTL-based caching in SIMD R Drive.

Documentation

Install

cargo add simd-r-drive-extensions

Usage

Working with Option<T>

use simd_r_drive::DataStore;
use simd_r_drive_extensions::StorageOptionExt;
use std::path::PathBuf;

let storage = DataStore::open(&PathBuf::from("test_store.bin")).unwrap();

// Write Some value
storage.write_option(b"key_with_some_value", Some(&42)).unwrap();
assert_eq!(
    storage.read_option::<i32>(b"key_with_some_value").expect("Failed to read key1"),
    Some(42)
);

// Write None
storage.write_option::<i32>(b"key_with_none_value", None).unwrap();
assert_eq!(
    storage.read_option::<i32>(b"key_with_none_value").expect("Failed to read key2"),
    None
);

// Errors on non-existent keys
assert!(storage.read_option::<i32>(b"non_existent_key").is_err());

Working with TTL-based Caching

use simd_r_drive::DataStore;
use simd_r_drive_extensions::StorageCacheExt;
use std::path::PathBuf;
use std::thread::sleep;
use std::time::Duration;

let storage = DataStore::open(&PathBuf::from("test_store.bin")).unwrap();

// Write value with a TTL of 5 seconds
storage.write_with_ttl(b"key_with_ttl", &42, 5).unwrap();
assert_eq!(
    storage.read_with_ttl::<i32>(b"key_with_ttl").expect("Failed to read key"),
    Some(42)
);

// Wait for TTL to expire
sleep(Duration::from_secs(6));
assert_eq!(
    storage.read_with_ttl::<i32>(b"key_with_ttl").expect("Failed to read key"),
    None // Key should be expired and removed
);

Implementation Details

• Uses a predefined tombstone marker ([0xFF, 0xFE]) to represent None.
• TTL values are stored as a binary prefix before the actual value.
• Values are serialized using bincode.
• ⚠️ Unlike SIMD R Drive, values are non-zero-copy, as they require deserialization.
• TTL-based storage will automatically evict expired values upon read to prevent stale data.

License

Licensed under the Apache-2.0 License.