Struct BufferPool 

pub struct BufferPool {
    pub stats: BufferPoolStats,
    /* private fields */
}

The buffer pool - caches pages in memory

Fields

stats: BufferPoolStats

Statistics

Implementations

impl BufferPool

pub fn new(capacity: usize, file_manager: Arc<FileManager>) -> Self

Create a new buffer pool with default Clock eviction

pub fn with_policy( capacity: usize, file_manager: Arc<FileManager>, policy_type: EvictionPolicyType, ) -> Self

Create a new buffer pool with specified eviction policy

pub fn eviction_policy_type(&self) -> EvictionPolicyType

Get the eviction policy type

pub fn eviction_policy_name(&self) -> &'static str

Get the eviction policy name

pub fn get_page(&self, page_id: PageId) -> Result<PageGuard>

Get a page for reading

pub fn get_page_for_write(&self, page_id: PageId) -> Result<PageGuardMut>

Get a page for writing

pub fn allocate_page( &self, page_type: PageType, ) -> Result<(PageId, PageGuardMut)>

Allocate a new page

pub fn copy_page(&self, page_id: PageId) -> Result<(PageId, PageGuardMut)>

Copy a page for modification (copy-on-write)

pub fn flush_all(&self) -> Result<()>

Flush all dirty pages

Skips pages owned by active (uncommitted) transactions to prevent uncommitted data from being persisted.

pub fn flush_page(&self, page_id: PageId) -> Result<()>

Flush a specific page

pub fn register_active_txn(&self, txn_id: TransactionId)

Register a transaction as active (its dirty pages can’t be evicted)

pub fn unregister_active_txn(&self, txn_id: TransactionId)

Unregister a transaction (called on commit or abort)

pub fn get_page_for_write_in_txn( &self, page_id: PageId, txn_id: TransactionId, ) -> Result<PageGuardMut>

Get a page for write within a transaction context

This marks the page as dirty and records the transaction that modified it. Pages owned by uncommitted transactions cannot be evicted.

pub fn allocate_page_in_txn( &self, page_type: PageType, txn_id: TransactionId, ) -> Result<(PageId, PageGuardMut)>

Allocate a new page within a transaction context

pub fn flush_transaction(&self, txn_id: TransactionId) -> Result<()>

Flush only pages dirtied by a specific transaction

Called during commit to persist the transaction’s changes. After flushing, clears the transaction ownership from the pages.

pub fn discard_transaction(&self, txn_id: TransactionId) -> Result<()>

Discard dirty pages from an aborted transaction

This clears the dirty flag and transaction ownership for pages that were modified by the aborted transaction, effectively discarding their uncommitted changes.

Note: The in-memory page data still contains the aborted writes, but since the dirty flag is cleared, they won’t be persisted. When the page is evicted and re-read, the original data is restored.

pub fn size(&self) -> usize

Get the number of pages in the buffer pool

pub fn capacity(&self) -> usize

Get the capacity of the buffer pool

pub fn stats_snapshot(&self) -> BufferPoolStatsSnapshot

Get a snapshot of current statistics

Trait Implementations

impl Drop for BufferPool

fn drop(&mut self)

Executes the destructor for this type.