Struct WalGeneration 

pub struct WalGeneration {
    pub checkpoint_seq: u32,
    pub salt: Option<WalSalt>,
}

R858-B19 — the identity of one WAL generation: the checkpoint sequence and the header salt that actually distinguishes it. This is what tail_frames compares across calls, what the watermark sidecar persists, and what a generation manifest stamps.

salt: None means unknown generation, and unknown is a value here, not a missing one: it arises from a sidecar or manifest written before this field existed, or from a WAL with no frames to read a salt out of. An unknown generation is never provably equal to anything — see WalGeneration::is_provably_same_as — so it forces a restart on the write side and a refusal on the restore side rather than a guess.

Fields

checkpoint_seq: u32

salt: Option<WalSalt>

Implementations

impl WalGeneration

pub fn is_provably_same_as(&self, other: &WalGeneration) -> bool

True only when both sides carry a known salt and every component agrees — i.e. only when these are provably the same WAL.

The asymmetry is the whole point. “Not provably the same” is treated as “different”, which costs a redundant re-upload (or a loud restore refusal) in the worst case. The opposite default — “no evidence of a change, so assume it is the same WAL” — is what spliced two WAL generations into one chain and restored a plausible wrong image.

Trait Implementations

impl Clone for WalGeneration

fn clone(&self) -> WalGeneration

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for WalGeneration

impl Debug for WalGeneration

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

Formats the value using the given formatter.

impl Default for WalGeneration

fn default() -> WalGeneration

Returns the “default value” for a type.

impl Eq for WalGeneration

impl PartialEq for WalGeneration

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for WalGeneration