Struct Config 

pub struct Config { /* private fields */ }

Tunables for a Pool.

Sizing is per-shard

compio is a thread-per-core runtime, so this pool keeps one independent shard per runtime thread (see the crate docs). Config::max_size and Config::min_idle therefore apply per shard, not to the process. A pool with max_size = 8 running on 4 compio threads can hold up to 32 connections in total.

This is deliberate: a global cap requires a cross-thread semaphore on the acquire fast path, which is exactly the contention thread-per-core runtimes exist to avoid.

Implementations

impl Config

pub fn new() -> Self

Starts from the defaults.

pub fn max_size(self, n: usize) -> Self

Maximum live connections per runtime thread. Must be non-zero.

pub fn min_idle(self, n: usize) -> Self

Idle connections each shard keeps thread-locally. Clamped to max_size.

This doubles as the split point between local caching and sharing: with a Reservoir installed, returned connections beyond min_idle are parked for other threads to claim. Leaving it at 0 therefore means every connection goes back to the shared stack and each checkout pays a mutex. Set it to your steady-state per-thread concurrency to keep the hot path lock-free and share only the surplus.

pub fn acquire_timeout(self, t: impl Into<Option<Duration>>) -> Self

How long Pool::acquire waits before returning Error::Timeout. None waits forever.

pub fn max_lifetime(self, t: impl Into<Option<Duration>>) -> Self

Hard age cap; a connection older than this is closed instead of reused.

pub fn idle_timeout(self, t: impl Into<Option<Duration>>) -> Self

How long a connection may sit unused in the free list before being reaped.

pub fn max_uses(self, n: impl Into<Option<u64>>) -> Self

Retire a connection after this many checkouts.

pub fn reap_interval(self, t: Duration) -> Self

How often each shard’s background reaper runs.

The reaper is what actually enforces idle_timeout and max_lifetime on connections nobody is asking for, and what refills min_idle.

Trait Implementations

impl Clone for Config

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Config

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

Formats the value using the given formatter.

impl Default for Config

fn default() -> Self

Returns the “default value” for a type.