Struct Pool 

pub struct Pool { /* private fields */ }

A pool of buffer frames with clock (second-chance FIFO) eviction.

Each pool manages a fixed set of frames. The buffer manager uses two pools: one for reads (70%) and one for writes (30%).

Implementations

impl Pool

pub fn new(num_frames: u32) -> Self

Create a new pool with the given number of frames.

pub fn frame(&self, idx: FrameIdx) -> &Frame

Get a reference to a frame by index.

pub fn num_frames(&self) -> u32

Get the number of frames in this pool.

pub fn find_evictable(&self) -> Option<FrameIdx>

Find an evictable frame using the clock (second-chance) algorithm.

Returns the index of an evictable frame, or None if all frames are pinned. A frame is evictable if it is not pinned. If it has the recently_used flag, we clear it and skip to the next frame (second chance).

We scan at most 2 * num_frames to ensure we complete a full cycle with cleared flags before giving up.

pub fn find_empty(&self) -> Option<FrameIdx>

Find the first empty (invalid page) frame.

pub fn dirty_count(&self) -> u32

Count the number of dirty frames.

pub fn pinned_count(&self) -> u32

Count the number of pinned frames.

pub fn loaded_count(&self) -> u32

Count the number of frames with valid pages loaded.