Struct BufferPool 

pub struct BufferPool { /* private fields */ }

Thread-safe buffer pool with CLOCK eviction.

Implementations

impl BufferPool

pub fn new(capacity: usize) -> Self

Create a buffer pool that may grow to capacity frame slots.

Frames are allocated on demand rather than up front: each frame owns a full page buffer, so eager allocation costs capacity * 64KB per open database regardless of use. A process holding many open databases (the platform gateway keeps an LRU of per user databases) pays only for pages actually touched.

pub fn fetch_page( &self, page_id: PageId, pm: &mut PageManager, ) -> MenteResult<Box<Page>>

Fetch a page into the pool (loading from disk if necessary).

The page is automatically pinned (pin_count incremented). Caller must call unpin_page when done.

pub fn pin_page(&self, page_id: PageId) -> MenteResult<()>

Increment the pin count of a page already in the pool.

pub fn unpin_page(&self, page_id: PageId, dirty: bool) -> MenteResult<()>

Decrement pin count and optionally mark the page dirty.

pub fn invalidate(&self, page_id: PageId)

Drop a page from the pool without flushing, discarding any dirty state.

Used when a page is freed: the on-disk state is already authoritative, so a stale cached copy must never be served or flushed back. A no-op if the page is not cached.

pub fn update_page(&self, page_id: PageId, page: &Page) -> MenteResult<()>

Replace the cached copy of a page and mark it dirty.

pub fn flush_page( &self, page_id: PageId, pm: &mut PageManager, ) -> MenteResult<()>

Flush a single dirty page to disk.

pub fn flush_all(&self, pm: &mut PageManager) -> MenteResult<()>

Flush all dirty pages to disk.