Skip leadership check if the etcd instance is active processing heartbeat

Signed-off-by: Benjamin Wang <benjamin.ahrtr@gmail.com>

server/etcdserver/server.go

@@ -904,10 +904,26 @@ func (s *EtcdServer) revokeExpiredLeases(leases []*lease.Lease) {
 	})
 }
 
+// isActive checks if the etcd instance is still actively processing the
+// heartbeat message (ticks). It returns false if no heartbeat has been
+// received within 3 * tickMs.
+func (s *EtcdServer) isActive() bool {
+	latestTickTs := s.r.getLatestTickTs()
+	threshold := 3 * time.Duration(s.Cfg.TickMs) * time.Millisecond
+	return latestTickTs.Add(threshold).After(time.Now())
+}
+
 // ensureLeadership checks whether current member is still the leader.
 func (s *EtcdServer) ensureLeadership() bool {
 	lg := s.Logger()
 
+	if s.isActive() {
+		lg.Debug("The member is active, skip checking leadership",
+			zap.Time("latestTickTs", s.r.getLatestTickTs()),
+			zap.Time("now", time.Now()))
+		return true
+	}
+
 	ctx, cancel := context.WithTimeout(s.ctx, s.Cfg.ReqTimeout())
 	defer cancel()
 	if err := s.linearizableReadNotify(ctx); err != nil {