Quick Pool

High Performance Async Generic Pool

Usage

DBCP

Database	Backend	Adapter	Version
PostgreSQL	tokio-postgres	qp-postgres

Example

use async_trait::async_trait;
use qp::resource::Manage;
use qp::{Pool, Pooled};

pub struct IntManager;

#[async_trait]
impl Manage for IntManager {
    type Output = i32;
    type Error = ();

    async fn try_create(&self) -> Result<Self::Output, Self::Error> {
        Ok(0)
    }

    async fn validate(&self, resource: &Self::Output) -> bool {
        resource >= &0
    }
}

#[tokio::main]
async fn main() {
    let pool = Pool::new(IntManager, 1); // max_size=1

    dbg!(pool.max_size()); // 1
    dbg!(pool.size()); // 1

    // create a resource when the pool is empty or all resources are occupied.
    let mut int = pool.acquire().await.unwrap();
    *int = 1;
    dbg!(*int); // 1
    dbg!(Pooled::is_valid(&int).await); // true; validate the resource.

    dbg!(pool.size()); // 0

    // release the resource and put it back to the pool.
    drop(int);

    let mut int = pool.acquire().await.unwrap();
    dbg!(*int); // 1
    *int = 100;
    drop(int);

    let mut int = pool.acquire().await.unwrap();
    dbg!(*int); // 100
    *int = -1; // the resource will be disposed because `validate` is false.
    dbg!(Pooled::is_valid(&int).await); // false
    drop(int);

    let int = pool.acquire_unchecked().await.unwrap();
    dbg!(*int); // -1; no validation before acquiring.
    drop(int);

    let int = pool.acquire().await.unwrap();
    dbg!(*int); // 0; old resource is disposed and create new one.

    // take the resource from the pool.
    let raw_int: i32 = Pooled::take(int); // raw resource
    dbg!(raw_int); // 0
    drop(raw_int);

    let _int = pool.acquire().await.unwrap();
    // `_int` will be auto released by `Pooled` destructor.
}

Alternatives

Crate	Version
bb8
deadpool
mobc
r2d2

bb8 vs qp

bb8 implements a resource waiter queue using futures-channel and uses the parking_lot for mutex.

On the other hand, qp uses a lock-free waiter queue using crossbeam-queue. qp doesn't use mutex.

deadpool vs qp

deadpool implements a idle resource queue using VecDeque and Mutex and controls access to resources using tokio::sync::Semaphore.

On the other hand, qp uses a semaphore implemented using a lock-free queue. Also, qp is a lock-free data structure that never uses lock in idle resource queue.

Performance Comparison

Resource Acquisition Time Benchmark

For more information, see Rust Pool Benchmark.

License

Copyright (c) 2022 Seungjae Park

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Quick Pool is licensed under the MIT License.