Struct ReadPool 

pub struct ReadPool { /* private fields */ }

A bounded pool of reader connections. Clones share one pool.

Implementations

impl ReadPool

pub fn from_opener( cap: usize, open: impl Fn() -> Result<Connection> + Send + Sync + 'static, ) -> Result<Self>

A pool whose readers come from open, called once now to check it works and again for each new reader. The pool enforces cap and the closed and wait rules; query_only and other reader setup are the opener’s job. Intended for tests that need a pool over a connection they build themselves. Use DbOptions::open_read_pool for a real database.

pub fn get(&self) -> Result<PooledReadConnection>

Checks out an idle reader, opens a new one while under the cap, or waits for a return. Fails with DbError::ReadPoolClosed once the pool is closed, including while waiting. The wait has no bound; use Self::get_timeout to give up after a deadline.

pub fn get_timeout( &self, timeout: Duration, ) -> Result<Option<PooledReadConnection>>

Self::get with a bounded wait. Returns Ok(Some(reader)) as soon as a reader is idle or can be opened under the cap, and Ok(None) if none frees up within timeout. A zero timeout never waits: it returns an idle or newly opened reader, or Ok(None). If the pool is closed, or closes while waiting, the result is DbError::ReadPoolClosed, never Ok(None). Opening a new reader is not bounded by timeout. A timeout too large for the clock waits in bounded slices until a reader frees up or the pool closes.

pub fn close(&self)

Stops handing out readers and drops the idle ones now. A reader still checked out closes when it is returned. Calling it again does nothing.

pub fn close_and_wait(&self, timeout: Duration) -> Result<()>

Self::close, then waits up to timeout for every checked-out reader to be returned. Ok(()) means every connection is closed and its database file released. Otherwise it returns DbError::ReadPoolCloseTimeout with the number still out. Do not call it while holding a reader from this pool: that reader cannot come back, so the call times out. A timeout too large for the clock waits in bounded slices until the readers return.

pub fn capacity(&self) -> usize

pub fn idle_len(&self) -> usize

pub fn total_len(&self) -> usize

Trait Implementations

impl Clone for ReadPool

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.