Struct mysql::Pool

pub struct Pool { /* private fields */ }

Pool serves to provide you with a PooledConn’s. However you can prepare statements directly on Pool without invoking Pool::get_conn.

Pool will hold at least min connections and will create as many as max connections with possible overhead of one connection per alive thread.

Example of multithreaded Pool usage:

use mysql::{Pool, Opts};
use std::thread;

fn get_opts() -> Opts {
      // ...
}

let opts = get_opts();
let pool = Pool::new(opts).unwrap();
let mut threads = Vec::new();
for _ in 0..100 {
    let pool = pool.clone();
    threads.push(thread::spawn(move || {
        let mut result = pool.prep_exec("SELECT 1", ()).unwrap();
        assert_eq!(result.next().unwrap().unwrap().unwrap(), vec![1.into()]);
    }));
}
for t in threads.into_iter() {
    assert!(t.join().is_ok());
}

For more info on how to work with mysql connection please look at PooledConn documentation.

Implementations

impl Pool

pub fn new<T: Into<Opts>>(opts: T) -> MyResult<Pool>

Creates new pool with min = 10 and max = 100.

pub fn new_manual<T: Into<Opts>>(
    min: usize,
    max: usize,
    opts: T
) -> MyResult<Pool>

Same as new but you can set min and max.

pub fn use_cache(&mut self, use_cache: bool)

A way to turn off searching for cached statement (on by default).

If turned on, then calls to Pool::{prepare, prep_exec, first_exec} will search for cached statement through all connections in the pool. Useless if the value of the stmt_cache_size option is 0.

pub fn check_health(&mut self, check_health: bool)

A way to turn off connection health check on each call to get_conn and prepare (prep_exec is not affected) (on by default).

pub fn get_conn(&self) -> MyResult<PooledConn>

Gives you a PooledConn.

Pool will check that connection is alive via Conn::ping and will call Conn::reset if necessary.

pub fn try_get_conn(&self, timeout_ms: u32) -> MyResult<PooledConn>

Will try to get connection for a duration of timeout_ms milliseconds.

Failure

This function will return Error::DriverError(DriverError::Timeout) if timeout was reached while waiting for new connection to become available.

pub fn prepare<T: AsRef<str>>(&self, query: T) -> MyResult<Stmt<'static>>

Will prepare statement. See Conn::prepare.

It will try to find connection which has this statement cached.

pub fn prep_exec<A, T>(
    &self,
    query: A,
    params: T
) -> MyResult<QueryResult<'static>>where
    A: AsRef<str>,
    T: Into<Params>,

Shortcut for pool.get_conn()?.prep_exec(..). See Conn::prep_exec.

It will try to find connection which has this statement cached.

pub fn first_exec<Q, P>(&self, query: Q, params: P) -> MyResult<Option<Row>>where
    Q: AsRef<str>,
    P: Into<Params>,

See Conn::first_exec.

pub fn start_transaction(
    &self,
    consistent_snapshot: bool,
    isolation_level: Option<IsolationLevel>,
    readonly: Option<bool>
) -> MyResult<Transaction<'static>>

Shortcut for pool.get_conn()?.start_transaction(..).

Trait Implementations

impl Clone for Pool

fn clone(&self) -> Pool

Returns a copy 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.