# bb8
[](https://docs.rs/bb8/)
[](https://crates.io/crates/bb8)
[](https://github.com/djc/bb8/actions?query=workflow%3ACI)
[](https://codecov.io/gh/djc/bb8)
[](https://discord.gg/E4DuUP83V2)
[](./LICENSE)
A full-featured connection pool, designed for asynchronous connections (using
tokio). Originally based on [r2d2](https://github.com/sfackler/r2d2).
Opening a new database connection every time one is needed is both inefficient
and can lead to resource exhaustion under high traffic conditions. A connection
pool maintains a set of open connections to a database, handing them out for
repeated use.
bb8 is agnostic to the connection type it is managing. Implementors of the
`ManageConnection` trait provide the database-specific logic to create and
check the health of connections.
A (possibly not exhaustive) list of adapters for different backends:
[tokio-postgres](https://github.com/sfackler/rust-postgres) | [bb8-postgres](https://crates.io/crates/bb8-postgres) (in-tree)
[redis](https://github.com/mitsuhiko/redis-rs) | [bb8-redis](https://crates.io/crates/bb8-redis) (in-tree)
[redis_cluster_async](https://crates.io/crates/redis_cluster_async) | [bb8-redis-cluster](https://crates.io/crates/bb8-redis-cluster)
[rsmq](https://github.com/smrchy/rsmq) | [rsmq_async](https://crates.io/crates/rsmq_async)
[bolt-client](https://crates.io/crates/bolt-client) | [bb8-bolt](https://crates.io/crates/bb8-bolt)
[diesel](https://crates.io/crates/diesel) | [diesel_async](https://github.com/weiznich/diesel_async)
[tiberius](https://crates.io/crates/tiberius) | [bb8-tiberius](https://crates.io/crates/bb8-tiberius)
[nebula-client](https://crates.io/crates/nebula-client) | [bb8-nebula](https://crates.io/crates/bb8-nebula)
[memcache-async](https://github.com/vavrusa/memcache-async) | [bb8-memcached](https://crates.io/crates/bb8-memcached)
[lapin](https://crates.io/crates/lapin) | [bb8-lapin](https://crates.io/crates/bb8-lapin)
[arangors](https://crates.io/crates/arangors) | [bb8-arangodb](https://crates.io/crates/bb8-arangodb)
[tonic](https://crates.io/crates/tonic) | [bb8-tonic](https://crates.io/crates/bb8-tonic)
## Example
Using an imaginary "foodb" database.
```rust
#[tokio::main]
async fn main() {
let manager = bb8_foodb::FooConnectionManager::new("localhost:1234");
let pool = bb8::Pool::builder()
.max_size(15)
.build(manager)
.await
.unwrap();
for _ in 0..20 {
let pool = pool.clone();
tokio::spawn(async move {
let conn = pool.get().await.unwrap();
// use the connection
// it will be returned to the pool when it falls out of scope.
});
}
}
```
## License
Licensed under the MIT license ([LICENSE](LICENSE)).
### Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you shall be licensed as above, without any
additional terms or conditions.