[authority] Remove unused cached checkpoint number (#4690)

crates/sui-core/src/authority.rs

@@ -37,7 +37,7 @@ use std::{
  collections::{HashMap, VecDeque},
  pin::Pin,
  sync::{
- atomic::{AtomicBool, AtomicU64, AtomicUsize, Ordering},
+ atomic::{AtomicBool, AtomicUsize, Ordering},
  Arc,
  },
 };
@@ -410,9 +410,6 @@ pub struct AuthorityState {
 
  pub metrics: Arc<AuthorityMetrics>,
 
- // Cache the latest checkpoint number to avoid expensive locking to access checkpoint store
- latest_checkpoint_num: AtomicU64,
-
  /// A channel to tell consensus to reconfigure.
  tx_reconfigure_consensus: Sender<ReconfigConsensusMessage>,
 }
@@ -1251,7 +1248,6 @@ impl AuthorityState {
  ),
  consensus_guardrail: AtomicUsize::new(0),
  metrics: Arc::new(AuthorityMetrics::new(prometheus_registry)),
- latest_checkpoint_num: AtomicU64::new(0),
  tx_reconfigure_consensus,
  };
 
@@ -2010,10 +2006,6 @@ impl ExecutionState for AuthorityState {
  // to persist the consensus index. If the validator crashes, this transaction
  // may be resent to the checkpoint logic that will simply ignore it.
 
- // Cache the next checkpoint number if it changes.
- self.latest_checkpoint_num
- .store(checkpoint.next_checkpoint(), Ordering::Relaxed);
-
  // TODO: At this point we should know whether we want to change epoch. If we do,
  // we should have (i) the new committee and (ii) the new keypair of this authority.
  // We then call: