Struct AckTracker 

pub struct AckTracker { /* private fields */ }

Tracks transaction commit acknowledgments from replicas.

When the master commits a transaction, it may need to wait for one or more replicas to acknowledge receipt before considering the transaction durable. The AckTracker manages pending acknowledgments, recording which replicas have acked which VLSNs, and detecting when sufficient acks have been received or when ack timeouts have occurred.

Implementations

impl AckTracker

pub fn new() -> Self

Create a new ack tracker.

pub fn register(&self, vlsn: u64, needed_acks: u32)

Register a new VLSN that needs acknowledgments.

If the VLSN is already registered, this is a no-op (the existing registration is preserved).

pub fn record_ack(&self, vlsn: u64, replica_name: &str) -> AckResult

Record an acknowledgment from a replica for a VLSN.

Returns the result indicating whether the ack was accepted and whether it satisfied the durability requirement.

pub fn wait_until_satisfied<F: Fn() -> bool>( &self, vlsn: u64, timeout: Duration, should_abort: F, ) -> bool

Block until vlsn has sufficient acks, the timeout elapses, or should_abort returns true (e.g. shutdown). Returns true if the VLSN became satisfied, false on timeout/abort. Replaces the prior spin-sleep loop — committers park on the condvar and are woken by record_ack (JE FeederTxns.TxnInfo CountDownLatch.await).

pub fn wait_for_predicate<P, A>( &self, timeout: Duration, predicate: P, should_abort: A, ) -> bool

where P: Fn() -> bool, A: Fn() -> bool,

REP-9: park on the ack-signal condvar until predicate() returns true, timeout elapses, or should_abort() returns true. Returns true iff predicate was satisfied. This is the high-water-mark equivalent of wait_until_satisfied for callers that count acks themselves via the per-replica high-water marks (JE FeederManager.getNumCurrentAckFeeders(commitVLSN) counts feeders with getReplicaTxnEndVLSN() >= commitVLSN, not an exact-VLSN match).

pub fn notify_waiters(&self)

REP-9: wake any committer parked in wait_for_predicate / wait_until_satisfied. Used by env.record_ack after it advances a feeder high-water mark, because satisfaction is now decided by the per-replica high-water count (not an exact-VLSN registration), so a record_ack for a VLSN with no exact registration must still wake waiters whose commit_vlsn predicate has just become true.

pub fn is_satisfied(&self, vlsn: u64) -> bool

Check if a VLSN has sufficient acks.

pub fn received_count(&self, vlsn: u64) -> Option<u32>

Number of distinct replica acks recorded for vlsn, or None if no registration exists for that VLSN.

Used by the F1 commit-coordinator path to report the partial ack count when a commit times out without satisfying the configured ReplicaAckPolicy.

pub fn cleanup_through(&self, vlsn: u64)

Remove all pending acks for VLSNs <= the given value.

This is used to clean up acks for transactions that have been durably committed and no longer need tracking.

pub fn pending_count(&self) -> usize

Get the number of pending (unsatisfied) acks.

pub fn check_timeouts(&self, timeout: Duration) -> Vec<u64>

Check for timed-out acks and return their VLSNs.

An ack is considered timed out if it was registered more than timeout ago and has not yet been satisfied.

Side effect: for each unsatisfied, timed-out pending ack found during this scan, total_timeouts is incremented by one.

pub fn get_total_acks(&self) -> u64

Get total number of acks received across all VLSNs.

pub fn get_total_timeouts(&self) -> u64

Get total number of ack timeouts.

Trait Implementations

impl Default for AckTracker

fn default() -> Self

Returns the “default value” for a type.