Struct Pool 

pub struct Pool { /* private fields */ }

Asynchronous pool of MySql connections.

Actually Pool is a shared reference, i.e. every clone will lead to the same instance created with Pool::new. Also Pool satisfies Send and Sync, so you don’t have to wrap it into an Arc or Mutex.

Note that you will probably want to await Pool::disconnect before dropping the runtime, as otherwise you may end up with a number of connections that are not cleanly terminated.

Multi-runtime environments

Pool must not be shared across independent tokio runtimes. Each tokio::net::TcpStream inside a pooled connection is bound to the I/O driver of the runtime that established it; connections become invalid when that runtime shuts down. This is most likely to surface during graceful shutdown, when some runtimes exit before others while pooled connections are still in circulation. The pool’s background tasks ([Recycler], TTL interval) are also spawned on the first runtime to call Pool::get_conn and do not survive that runtime’s shutdown.

If your framework runs each worker on its own current_thread runtime (e.g. actix-server), create a separate Pool per worker rather than sharing one across all workers.

Implementations

impl Pool

pub fn new<O>(opts: O) -> Pool

where Opts: TryFrom<O>, <Opts as TryFrom<O>>::Error: Error,

Creates a new pool of connections.

Panic

It’ll panic if Opts::try_from(opts) returns error.

pub fn metrics(&self) -> Arc<Metrics>

Returns metrics for the connection pool.

pub fn from_url<T: AsRef<str>>(url: T) -> Result<Pool>

Creates a new pool of connections.

pub fn get_conn(&self) -> impl Future<Output = Result<Conn>>

Async function that resolves to Conn.

pub async fn start_transaction( &self, options: TxOpts, ) -> Result<Transaction<'static>>

Starts a new transaction.

pub async fn disconnect(self) -> Result<()>

Async function that disconnects this pool from the server and resolves to ().

Note: This Future won’t resolve until all active connections, taken from it, are dropped or disonnected. Also all pending and new get_conn()’s will resolve to error.

Trait Implementations

impl Clone for Pool

fn clone(&self) -> Pool

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Pool

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a> ToConnection<'a, 'static> for &'a Pool

fn to_connection(self) -> ToConnectionResult<'a, 'static>

Converts self to a connection.

impl ToConnection<'static, 'static> for Pool

fn to_connection(self) -> ToConnectionResult<'static, 'static>

Converts self to a connection.