Struct WALWriter 

pub struct WALWriter { /* private fields */ }

WAL writer for appending records to WAL file

Handles writing WAL records to disk with proper synchronization for crash recovery. Records are written in format:

[4 bytes: record size (little-endian u32)]
[N bytes: serialized record]

Durability

Each record is followed by an optional fsync for durability. For performance, multiple records can be batched before syncing.

Implementations

impl WALWriter

pub fn new(wal_path: PathBuf, start_lsn: u64) -> NativeResult<Self>

Create a new WAL writer

Arguments

• wal_path - Path to WAL file
• start_lsn - Starting LSN (default LSN_BEGIN for new WAL)

Returns

Returns error if WAL file exists but cannot be read.

pub fn current_lsn(&self) -> u64

Get current LSN

pub fn committed_lsn(&self) -> u64

Get committed LSN

pub fn write_header(&self) -> NativeResult<()>

Write WAL header (initializes new WAL file)

pub fn append(&mut self, record: &V3WALRecord) -> NativeResult<()>

Append a record to WAL buffer

Record is buffered until flush() is called or buffer threshold is reached.

pub fn flush(&mut self) -> NativeResult<()>

Flush buffered records to disk

Writes all buffered records and optionally syncs to disk.

pub fn commit(&mut self) -> NativeResult<()>

Mark records up to current LSN as committed

Updates the committed_lsn in WAL header. Requires flush to persist the updated header.

pub fn truncate(&self) -> NativeResult<()>

Truncate WAL file (after checkpoint)

Removes WAL records that are no longer needed.

pub fn page_allocate(&mut self, page_id: u64) -> NativeResult<u64>

Write page allocate record

pub fn page_free(&mut self, page_id: u64, checksum: u32) -> NativeResult<u64>

Write page free record

pub fn page_write( &mut self, page_id: u64, offset: u32, data: Vec<u8>, ) -> NativeResult<u64>

Write page write record

pub fn btree_split( &mut self, original_page_id: u64, new_page_id: u64, split_key: u64, page_type: bool, ) -> NativeResult<u64>

Write B+Tree split record

pub fn checkpoint( &mut self, root_page_id: u64, total_pages: u64, btree_height: u32, free_page_list_head: u64, header: &PersistentHeaderV3, ) -> NativeResult<u64>

Write checkpoint record

pub fn transaction_begin(&mut self, tx_id: u64) -> NativeResult<u64>

Write transaction begin record

pub fn transaction_commit(&mut self, tx_id: u64) -> NativeResult<u64>

Write transaction commit record

pub fn transaction_rollback(&mut self, tx_id: u64) -> NativeResult<u64>

Write transaction rollback record

pub fn edge_insert( &mut self, src: i64, dst: i64, direction: u8, page_id: u64, ) -> NativeResult<u64>

Write edge insert record

Records an edge insertion for WAL replay during crash recovery. The edge will be inserted into the edge cluster during recovery.

pub fn set_flush_threshold(&mut self, threshold: usize)

Set buffer flush threshold

Trait Implementations

impl Debug for WALWriter

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

Formats the value using the given formatter.