Struct Pool 

pub struct Pool { /* private fields */ }

A pool of reusable connections.

Implementations

impl Pool

pub async fn connect( url: &str, config: Option<PoolConfig>, ) -> Result<Self, Error>

Creates a pool from a postgres:// URL.

Pool settings are read from the URL (pool_size, min_connections, acquire_timeout, idle_timeout, max_lifetime); when config is Some, it overrides them entirely.

TLS

TLS is always required; plaintext connections are not possible.

sslmode	Chain verified	Hostname verified
require (default)	no	no
verify-ca	yes	no
verify-full	yes	yes

disable, prefer and allow are rejected. verify-ca and verify-full read trusted roots from sslrootcert (a PEM file) or the operating system trust store.

use postgresql::{Pool, PoolConfig};

// Pool of up to 16 connections, TLS required (default).
let pool = Pool::connect("postgres://user:pass@db.example.com/app?pool_size=16", None).await?;

// Verify the certificate chain and hostname; override the pool size.
let other = Pool::connect(
    "postgres://user:pass@db.example.com/app?sslmode=verify-full&sslrootcert=/etc/ssl/db-ca.pem",
    Some(PoolConfig { pool_size: 32, min_connections: 2, ..PoolConfig::default() }),
)
.await?;

Errors

Returns a configuration error for an invalid URL. Opening the min_connections is best-effort: if some cannot be established the pool starts with fewer and opens more on demand (the minimum is not maintained afterwards).

pub async fn get(&self) -> Result<PooledConnection, Error>

Acquires a connection, waiting up to the configured acquire timeout.

Errors

Returns Error::PoolClosed if the pool is closed, Error::PoolTimedOut if no connection becomes available in time, or a connection error if a new connection cannot be established.

pub async fn begin(&self) -> Result<Transaction, Error>

Acquires a connection and starts a transaction on it.

pub fn is_closed(&self) -> bool

Returns true if the pool has been closed.

pub fn close(&self)

Closes the pool and discards idle connections.

Connections still checked out are closed when they are returned, not reused.

Trait Implementations

impl Clone for Pool

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl ScriptExecutor for Pool

fn execute_script<'a>( &'a self, sql: &'a str, ) -> impl Future<Output = Result<u64, Error>> + Send + 'a

Runs one or more statements and returns the affected-row count of the last command.