Struct ConnectionPool 

pub struct ConnectionPool { /* private fields */ }

Lock-free connection pool using a lock-free idle queue and tokio::sync::Notify for efficient blocking when at capacity.

Design:

• Idle connections in SegQueue (lock-free, no contention).
• AtomicU32 tracks total connections (idle + borrowed).
• Notify wakes waiters when a connection is released.
• No mutexes, no spin-waiting, no semaphore overhead.

Implementations

impl ConnectionPool

pub async fn new(connection_string: &str, config: PoolConfig) -> Result<Self>

pub async fn acquire(&self) -> MCPResult<Arc<Client>>

Acquire a connection from the pool.

Fast path: pop from idle queue (lock-free, ~20ns). Slow path: create new connection (up to max_size), or block via Notify.

pub fn release(&self, conn: Arc<Client>)

Release a connection back to the pool.

pub fn active_count(&self) -> u32

pub fn max_size(&self) -> u32