async-skipdb 0.1.2

<div align="center">
<h1>SkipDB</h1>
</div>
<div align="center">

Blazing fast ACID and MVCC in memory database based on lock-free skiplist.

`async-skipdb` uses the same SSI (Serializable Snapshot Isolation) transaction model used in [`badger`](https://github.com/dgraph-io/badger).

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[<img alt="crates.io" src="https://img.shields.io/crates/d/skipdb?color=critical&logo=data:image/svg+xml;base64,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&style=for-the-badge" height="22">][crates-url]


English | [简体中文][zh-cn-url]

</div>

## Introduction

Blazing fast ACID and MVCC in memory database based on lock-free skiplist.

`async-skipdb` uses the same SSI (Serializable Snapshot Isolation) transaction model used in [`badger`](https://github.com/dgraph-io/badger).

For sync version, please see [`skipdb`](https://crates.io/crates/skipdb).

## Features

- ACID, MVCC, serializable snapshot isolation, concurrent safe and almost lock-free.
- No extra allocation and copy, there is no `Arc` wrapper for both key and value stored in the database, which means that users provide `K` and `V`, and database store `K` and `V` directly.
- Zero-copy and in-place compaction, which means there is no copy, no extra allocation when compacting.
- Concurrent execution of transactions, providing serializable snapshot isolation, avoiding write skews.
- Both read transaction and write transaction are `Send + Sync + 'static`, which means you do not need to handle annoying lifetime problem anymore.
- Lock-free and concurrent safe read transaction: the read transaction is totally concurrent safe and can be shared in multiple threads, there is no lock in read transaction.
- `BTreeMap` like user friendly API and all iterators implement `Iterator` trait, which means users use Rust powerful conbinators when iterating over the database.
- Runtime agnostic, `tokio`, `async-std`, `smol`, `wasm-bindgen-futures` and any other async runtime.
- 100% safe, skipdb sets `[forbid(unsafe_code)]`.

## Installation

- `tokio`

  ```toml
  [dependencies]
  async-skipdb = { version = "0.1", features = ["tokio"] }
  ```

- `async-std`

  ```toml
  [dependencies]
  async-skipdb = { version = "0.1", features = ["async-std"] }
  ```

- `smol`

  ```toml
  [dependencies]
  async-skipdb = { version = "0.1", features = ["smol"] }
  ```

- `wasm-bindgen-futures`

  ```toml
  [dependencies]
  async-skipdb = { version = "0.1", features = ["wasm"] }
  ```

## Example

- If your `K` implement `Hash`.

  ```rust
  use async_skipdb::equivalent::TokioEquivalentDb;

  #[derive(Debug)]
  struct Person {
    hobby: String,
    age: u8,
  }

  #[tokio::main]
  async fn main() {
    let db: TokioEquivalentDb<String, Person> = TokioEquivalentDb::new().await;
    
    {
      let alice = Person { hobby: "swim".to_string(), age: 20 };
      let bob = Person { hobby: "run".to_string(), age: 30 };

      let mut txn = db.write().await;
      txn.insert("Alice".to_string(), alice).unwrap();
      txn.insert("Bob".to_string(), bob).unwrap();

      {
        let alice = txn.get("Alice").unwrap().unwrap();
        assert_eq!(alice.value().age, 20);
        assert_eq!(alice.value().hobby, "swim");
      }

      txn.commit().await.unwrap();
    }

    {
      let txn = db.read().await;
      let alice = txn.get("Alice").unwrap();
      assert_eq!(alice.value().age, 20);
      assert_eq!(alice.value().hobby, "swim");

      let bob = txn.get("Bob").unwrap();
      assert_eq!(bob.value().age, 30);
      assert_eq!(bob.value().hobby, "run"); 
    }
  }
  ```

- If your key cannot implement `Hash` for some reasons.

  Then you can use `ComparableDb`, but this will require `K: CheapClone + Ord`, you can see [`cheap_clone`](https://crates.io/crates/cheap-clone) trait for more details.

  ```rust
  use async_skipdb::comparable::TokioComparableDb;

  #[derive(Debug)]
  struct Person {
    name: String,
    hobby: String,
    age: u8,
  }

  #[tokio::main]
  async fn main() {
    let db: TokioComparableDb<u64, Person> = TokioComparableDb::new().await;
  
    {
      let alice = Person { name: "Alice".to_string(), hobby: "swim".to_string(), age: 20 };
      let bob = Person { name: "Bob".to_string(), hobby: "run".to_string(), age: 30 };

      let mut txn = db.write().await;
      txn.insert(1, alice).unwrap();
      txn.insert(2, bob).unwrap();

      {
        let alice = txn.get(&1).unwrap().unwrap();
        assert_eq!(alice.value().name, "Alice");
        assert_eq!(alice.value().age, 20);
        assert_eq!(alice.value().hobby, "swim");
      }

      txn.commit().await.unwrap();
    }

    {
      let txn = db.read().await;
      let alice = txn.get(&1).unwrap();
      assert_eq!(alice.value().name, "Alice");
      assert_eq!(alice.value().age, 20);
      assert_eq!(alice.value().hobby, "swim");

      let bob = txn.get(&2).unwrap();
      assert_eq!(bob.value().name, "Bob");
      assert_eq!(bob.value().age, 30);
      assert_eq!(bob.value().hobby, "run"); 
    }
  }
  ```

#### License

`async-skipdb` is under the terms of both the MIT license and the
Apache License (Version 2.0).

See [LICENSE-APACHE](LICENSE-APACHE), [LICENSE-MIT](LICENSE-MIT) for details.

Copyright (c) 2024 Al Liu.

[Github-url]: https://github.com/al8n/skipdb/
[CI-url]: https://github.com/al8n/skipdb/actions/workflows/ci.yml
[doc-url]: https://docs.rs/async-skipdb
[crates-url]: https://crates.io/crates/async-skipdb
[codecov-url]: https://app.codecov.io/gh/al8n/skipdb/
[zh-cn-url]: https://github.com/al8n/skipdb/tree/main/README-zh_CN.md