pkg/member: Fixing residual counts in campaign times (tikv#8226) (tik…

…v#8230)

close tikv#8225

Signed-off-by: husharp <[email protected]>

Co-authored-by: husharp <[email protected]>

pkg/election/leadership.go

@@ -34,11 +34,12 @@ import (
 )
 
 const (
-	defaultCampaignTimesSlot   = 10
-	watchLoopUnhealthyTimeout  = 60 * time.Second
-	campaignTimesRecordTimeout = 5 * time.Minute
+	defaultCampaignTimesSlot  = 10
+	watchLoopUnhealthyTimeout = 60 * time.Second
 )
 
+var campaignTimesRecordTimeout = 5 * time.Minute
+
 // GetLeader gets the corresponding leader from etcd by given leaderPath (as the key).
 func GetLeader(c *clientv3.Client, leaderPath string) (*pdpb.Member, int64, error) {
 	leader := &pdpb.Member{}
@@ -114,6 +115,7 @@ func (ls *Leadership) GetLeaderKey() string {
 }
 
 // GetCampaignTimesNum is used to get the campaign times of the leader within `campaignTimesRecordTimeout`.
+// Need to make sure `AddCampaignTimes` is called before this function.
 func (ls *Leadership) GetCampaignTimesNum() int {
 	if ls == nil {
 		return 0
@@ -129,16 +131,16 @@ func (ls *Leadership) ResetCampaignTimes() {
 	ls.campaignTimes = make([]time.Time, 0, defaultCampaignTimesSlot)
 }
 
-// addCampaignTimes is used to add the campaign times of the leader.
-func (ls *Leadership) addCampaignTimes() {
+// AddCampaignTimes is used to add the campaign times of the leader.
+func (ls *Leadership) AddCampaignTimes() {
 	if ls == nil {
 		return
 	}
 	for i := len(ls.campaignTimes) - 1; i >= 0; i-- {
 		if time.Since(ls.campaignTimes[i]) > campaignTimesRecordTimeout {
 			// remove the time which is more than `campaignTimesRecordTimeout`
 			// array is sorted by time
-			ls.campaignTimes = ls.campaignTimes[i:]
+			ls.campaignTimes = ls.campaignTimes[i+1:]
 			break
 		}
 	}
@@ -148,7 +150,6 @@ func (ls *Leadership) addCampaignTimes() {
 
 // Campaign is used to campaign the leader with given lease and returns a leadership
 func (ls *Leadership) Campaign(leaseTimeout int64, leaderData string, cmps ...clientv3.Cmp) error {
-	ls.addCampaignTimes()
 	ls.leaderValue = leaderData
 	// Create a new lease to campaign
 	newLease := &lease{

pkg/election/leadership_test.go

@@ -262,3 +262,36 @@ func TestRequestProgress(t *testing.T) {
 	checkWatcherRequestProgress(false)
 	checkWatcherRequestProgress(true)
 }
+
+func TestCampaignTimes(t *testing.T) {
+	re := require.New(t)
+	_, client, clean := etcdutil.NewTestEtcdCluster(t, 1)
+	defer clean()
+	leadership := NewLeadership(client, "test_leader", "test_leader")
+
+	// all the campaign times are within the timeout.
+	campaignTimesRecordTimeout = 10 * time.Second
+	defer func() {
+		campaignTimesRecordTimeout = 5 * time.Minute
+	}()
+	for i := 0; i < 3; i++ {
+		leadership.AddCampaignTimes()
+		time.Sleep(100 * time.Millisecond)
+	}
+	re.Equal(3, leadership.GetCampaignTimesNum())
+
+	// only the last 2 records are valid.
+	campaignTimesRecordTimeout = 200 * time.Millisecond
+	for i := 0; i < 3; i++ {
+		leadership.AddCampaignTimes()
+		time.Sleep(100 * time.Millisecond)
+	}
+	re.Equal(2, leadership.GetCampaignTimesNum())
+
+	time.Sleep(200 * time.Millisecond)
+	// need to wait for the next addCampaignTimes to update the campaign time.
+	re.Equal(2, leadership.GetCampaignTimesNum())
+	// check campaign leader frequency.
+	leadership.AddCampaignTimes()
+	re.Equal(1, leadership.GetCampaignTimesNum())
+}

pkg/member/member.go

@@ -182,10 +182,11 @@ func (m *EmbeddedEtcdMember) GetLastLeaderUpdatedTime() time.Time {
 // and make it become a PD leader.
 // leader should be changed when campaign leader frequently.
 func (m *EmbeddedEtcdMember) CampaignLeader(ctx context.Context, leaseTimeout int64) error {
+	m.leadership.AddCampaignTimes()
 	failpoint.Inject("skipCampaignLeaderCheck", func() {
 		failpoint.Return(m.leadership.Campaign(leaseTimeout, m.MemberValue()))
 	})
-	if m.leadership.GetCampaignTimesNum() >= campaignLeaderFrequencyTimes {
+	if m.leadership.GetCampaignTimesNum() > campaignLeaderFrequencyTimes {
 		log.Warn("campaign times is too frequent, resign and campaign again",
 			zap.String("leader-name", m.Name()), zap.String("leader-key", m.GetLeaderPath()))
 		if err := m.ResignEtcdLeader(ctx, m.Name(), ""); err != nil {

tests/server/member/member_test.go

@@ -327,20 +327,26 @@ func TestCampaignLeaderFrequently(t *testing.T) {
 	re := require.New(t)
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	cluster, err := tests.NewTestCluster(ctx, 5)
+	cluster, err := tests.NewTestCluster(ctx, 3)
 	defer cluster.Destroy()
 	re.NoError(err)
 
 	err = cluster.RunInitialServers()
 	re.NoError(err)
+	// the 1st time campaign leader.
 	cluster.WaitLeader()
 	leader := cluster.GetLeader()
 	re.NotEmpty(cluster.GetLeader())
 
-	for i := 0; i < 3; i++ {
+	// need to prevent 3 times(including the above 1st time) campaign leader in 5 min.
+	for i := 0; i < 2; i++ {
 		cluster.GetServers()[cluster.GetLeader()].ResetPDLeader()
 		cluster.WaitLeader()
+		re.Equal(leader, cluster.GetLeader())
 	}
+	// check for the 4th time.
+	cluster.GetLeaderServer().ResetPDLeader()
+	cluster.WaitLeader()
 	// PD leader should be different from before because etcd leader changed.
 	re.NotEmpty(cluster.GetLeader())
 	re.NotEqual(leader, cluster.GetLeader())