lease/lessor: recheck if exprired lease is revoked

lease/lease_queue_test.go

@@ -53,7 +53,7 @@ func TestLeaseQueue(t *testing.T) {
 		t.Fatal("expect no more expiry lease")
 	}
 
-	if le.leaseHeap.Len() != 49 {
+	if le.leaseHeap.Len() != 50 {
 		t.Fatalf("expected lease heap pop, got %d", le.leaseHeap.Len())
 	}
 }

lease/lessor.go

@@ -50,6 +50,9 @@ var (
 	// maximum number of lease checkpoints to batch into a single consensus log entry
 	maxLeaseCheckpointBatchSize = 1000
 
+	// interval to check if the expired lease is revoked
+	expiredleaseRetryInterval = 3 * time.Second
+
 	ErrNotPrimary       = errors.New("not a primary lessor")
 	ErrLeaseNotFound    = errors.New("lease not found")
 	ErrLeaseExists      = errors.New("lease already exists")
@@ -650,15 +653,19 @@ func (le *lessor) expireExists() (l *Lease, ok bool, next bool) {
 		heap.Pop(&le.leaseHeap) // O(log N)
 		return nil, false, true
 	}
-
-	if time.Now().UnixNano() < item.time /* expiration time */ {
+	now := time.Now()
+	if now.UnixNano() < item.time /* expiration time */ {
 		// Candidate expirations are caught up, reinsert this item
 		// and no need to revoke (nothing is expiry)
 		return l, false, false
 	}
 	// if the lease is actually expired, add to the removal list. If it is not expired, we can ignore it because another entry will have been inserted into the heap
 
 	heap.Pop(&le.leaseHeap) // O(log N)
+
+	// recheck if revoke is complete after retry interval
+	item.time = now.Add(expiredleaseRetryInterval).UnixNano()
+	heap.Push(&le.leaseHeap, item)
 	return l, true, false
 }