Struct Pool 

pub struct Pool(/* private fields */);

Available on Unix and crate feature pool only.

A buffer pool over swap-backed extents. Cheap to clone; all clones share one budget and one backing store.

Implementations

impl Pool

pub fn new() -> Result<Pool>

Creates a pool, reserving one virtual region per size class. The pool starts with an unlimited budget — nothing is evicted until Pool::set_budget tunes it.

pub fn insert_with( &self, len: usize, hints: ChunkHints, codec: &'static dyn ExtentCodec, fill: impl FnOnce(&mut [u64]), ) -> ChunkHandle

Allocates a chunk of len words and fills it in place: fill receives the chunk’s slot memory directly and must overwrite all of it (the slot’s prior contents are unspecified). The returned handle starts UnbackedResident. A zero len returns a length-0 handle holding no slot; payloads beyond the largest size class fall back to a plain heap allocation, always resident, a prototype limitation. hints steer eviction and write-behind policy; callers without placement knowledge pass the default.

This is the zero-staging insert: serialization can write its single copy straight into pool memory, paying one page population instead of staging through caller-side buffers that fault their own pages and die immediately after.

codec is the chunk’s ExtentCodec, fixed for its lifetime: the pool invokes it whenever the chunk moves across the extent boundary, and takes no interest in the stored form it produces.

Relies on abort-on-panic: a panic in fill that was caught would leak the slot and its resident-bytes accounting. All hosting binaries abort via mz_ore::panic::install_enhanced_handler, and pool consumers are dataflow operators, never code hosted under a catch_unwind boundary the way the optimizer is.

pub fn stats(&self) -> PoolStats

Snapshot of the pool’s counters.

pub fn set_spill_threads(&self, threads: usize)

Enables or disables off-worker eviction I/O. The first call with threads > 0 spawns that many spill threads (spawn-once: later calls only toggle participation); threads == 0 falls back to inline eviction on the caller for subsequent victims, letting any queued work drain.

pub fn set_eager_backing(&self, eager: bool)

Enables or disables eager backing: when on, idle spill threads compress unbacked chunks to BackedResident ahead of pressure, so budget-driven eviction becomes a pure page release. Only meaningful with spill threads spawned.

pub fn set_budget(&self, budget_bytes: usize)

Retunes the resident-bytes budget in place and enforces it. Live handles share the new value immediately through their Arc<PoolInner>; a shrink takes effect by evicting on this call, a grow simply leaves more headroom for future inserts.

pub fn set_rss_target(&self, target_bytes: usize)

Retunes the ceiling on the pool’s total RSS — slots plus warm slots plus compressed-resident extents. The compressed tier’s capacity is the gap above the budget and warm cap; zero (the default) collapses the tier, paging extents out as soon as they are written. A shrink takes effect by paging out the oldest extents on this call.

Trait Implementations

impl Clone for Pool

fn clone(&self) -> Pool

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Pool

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

Formats the value using the given formatter.