Struct raftstore::store::util::RegionReadProgress

pub struct RegionReadProgress {
    core: Mutex<RegionReadProgressCore>,
    safe_ts: AtomicU64,
}

RegionReadProgress is used to keep track of the replica’s safe_ts, the replica can handle a read request directly without requiring leader lease or read index iff safe_ts >= read_ts (the read_ts is usually stale i.e seconds ago).

safe_ts is updated by the (apply index, safe ts) item:

if self.applied_index >= item.apply_index {
    self.safe_ts = max(self.safe_ts, item.safe_ts)
}

For the leader, the (apply index, safe ts) item is publish by the resolved-ts worker periodically. For the followers, the item is sync periodically from the leader through the CheckLeader rpc.

The intend is to make the item’s safe ts larger (more up to date) and apply index smaller (require less data)

Fields

core: Mutex<RegionReadProgressCore>

safe_ts: AtomicU64

Implementations

impl RegionReadProgress

pub fn new(applied_index: u64, cap: usize) -> RegionReadProgress

pub fn update_applied(&self, applied: u64)

pub fn update_safe_ts(&self, apply_index: u64, ts: u64)

pub fn clear(&self)

pub fn read_state(&self) -> ReadState

pub fn safe_ts(&self) -> u64

Trait Implementations

impl Debug for RegionReadProgress

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

Formats the value using the given formatter.

impl Default for RegionReadProgress

fn default() -> RegionReadProgress

Returns the “default value” for a type.