Struct ClockProCache 

pub struct ClockProCache { /* private fields */ }

Clock-Pro adaptive page cache

Algorithm Overview

1. Cold pages: Recently accessed once. These may be promoted to hot if accessed again before eviction (reuse distance < test size).

2. Hot pages: Frequently accessed. Protected from eviction until demoted to cold.

3. Test pages: Ghost entries tracking recently evicted cold pages. If a test page is accessed, it indicates we should increase hot space.

Adaptive Sizing

The hot/cold ratio adjusts based on access patterns:

• Access to test page → increase hot space (working set growing)
• Cold page eviction without test hit → decrease hot space

Implementations

impl ClockProCache

pub fn new(capacity: usize) -> Self

Create new cache with default settings

pub fn with_page_size(capacity: usize, page_size: usize) -> Self

Create with specific page size

pub fn get(&self, page_id: &PageId) -> Option<Arc<CachedPage>>

Get a page from cache

pub fn insert(&self, page_id: PageId, data: Vec<u8>) -> Arc<CachedPage>

Insert a page into cache

pub fn insert_pinned(&self, page_id: PageId, data: Vec<u8>) -> Arc<CachedPage>

Insert with pinning

pub fn stats(&self) -> &CacheStats

Get statistics

pub fn len(&self) -> usize

Get current size

pub fn is_empty(&self) -> bool

Check if empty

pub fn capacity(&self) -> usize

Get capacity

pub fn hot_ratio(&self) -> f64

Get hot ratio

pub fn clear(&self)

Clear cache

pub fn memory_usage(&self) -> usize

Get memory usage in bytes