Struct WalEntry 

pub struct WalEntry {
    pub seq_num: u64,
    pub tx_id: u64,
    pub op_type: WalOpType,
    pub key: Vec<u8>,
    pub value: Vec<u8>,
    pub timestamp: u64,
    pub checksum: u64,
}

A single decoded entry in the write-ahead log.

Fields

seq_num: u64

Monotonically increasing sequence number assigned at write time.

tx_id: u64

Transaction identifier (0 = no transaction / standalone write).

op_type: WalOpType

Operation type.

key: Vec<u8>

Key bytes (may be empty for Begin/Commit/Rollback/Checkpoint).

value: Vec<u8>

Value bytes (may be empty for Delete/Begin/Commit/Rollback/Checkpoint).

timestamp: u64

Unix timestamp in nanoseconds captured at write time.

checksum: u64

FNV-1a 64-bit checksum of all preceding bytes in the encoded entry.

Implementations

impl WalEntry

pub fn encode(&self) -> Vec<u8>

Encodes this entry to its wire format.

Layout: [magic(4)][seq_num(8)][tx_id(8)][op_type(1)][key_len(4)][key(n)] [value_len(4)][value(m)][timestamp(8)][checksum(8)]

pub fn decode(data: &[u8], offset: usize) -> Result<(WalEntry, usize), WalError>

Attempts to decode one entry starting at data[offset..].

Returns (entry, bytes_consumed) on success.

Errors

• WalError::InvalidMagic if the four-byte header does not match.
• WalError::CorruptedEntry if the buffer is too short or an unknown op-type is encountered.
• WalError::ChecksumMismatch if the stored checksum disagrees.

Trait Implementations

impl Clone for WalEntry

fn clone(&self) -> WalEntry

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WalEntry

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

Formats the value using the given formatter.

impl Eq for WalEntry

impl PartialEq for WalEntry

fn eq(&self, other: &WalEntry) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for WalEntry