Struct ReaderSlot 

pub struct ReaderSlot {
    pub pid: AtomicU32,
    pub snapshot_ts: AtomicU64,
    pub epoch: AtomicU32,
    pub last_heartbeat: AtomicU64,
    /* private fields */
}

Reader slot in shared memory (64 bytes = 1 cache line)

Each active reader registers in a slot to prevent GC from reclaiming versions it might need.

Fields

pid: AtomicU32

Process ID (0 = slot is free)

snapshot_ts: AtomicU64

Snapshot timestamp this reader is using

epoch: AtomicU32

Epoch number when reader registered

last_heartbeat: AtomicU64

Last heartbeat (microseconds since epoch)

Implementations

impl ReaderSlot

pub const fn empty() -> Self

Create an empty reader slot

pub fn is_free(&self) -> bool

Check if slot is free

pub fn try_claim(&self, my_pid: u32, snapshot_ts: u64, epoch: u32) -> bool

Try to claim this slot for reading

Returns true if successfully claimed.

pub fn release(&self, my_pid: u32)

Release this slot

pub fn heartbeat(&self)

Update heartbeat

pub fn is_stale(&self, now_us: u64) -> bool

Check if this slot is stale (process crashed or hung)

Trait Implementations

impl Debug for ReaderSlot

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

Formats the value using the given formatter.