Struct BackendIdlePool 

pub struct BackendIdlePool { /* private fields */ }

A bounded set of idle, authenticated backend connections, partitioned by connection identity. Cheap to clone-share behind an Arc.

Implementations

impl BackendIdlePool

pub fn new(max_idle_per_key: usize, max_total_idle: usize) -> Self

Create a pool that parks at most max_idle_per_key connections per (node,user,db) identity and max_total_idle across all identities. A floor of 1 is enforced on each so the pool always retains at least one reusable connection.

pub fn checkout(&self, key: &str) -> Option<TcpStream>

Take a live idle connection for key, or None if the pool has no usable one (caller then dials a fresh connection). Dead/stale parked connections are evicted in passing.

pub fn checkin(&self, key: &str, stream: TcpStream) -> bool

Park a (freshly reset) connection for reuse under key. Returns false when an idle cap (per-key OR global) is already reached — in that case the connection is dropped (closed) by being moved in and discarded, shedding excess capacity.

pub fn reap_idle(&self, max_age: Duration) -> usize

Drop parked connections that have been idle longer than max_age so a connection the backend has (or will) close on its own idle timeout is not handed out stale, and idle capacity is released back to the OS. Returns the number reaped. Intended to be called periodically by a background task.

pub fn idle_count(&self) -> usize

Total idle connections currently parked across all identities (O(1)).

pub fn max_total_idle(&self) -> usize

Global ceiling on parked idle connections.

pub fn reaped(&self) -> u64

Number of parked connections dropped by the idle reaper (TTL).

pub fn reuses(&self) -> u64

Number of checkout hits (connections reused rather than dialed fresh).

pub fn parked(&self) -> u64

Number of successful check-ins.

pub fn over_capacity(&self) -> u64

Number of check-ins refused for exceeding the per-key idle cap.

pub fn stale_evicted(&self) -> u64

Number of stale connections evicted at checkout.