fix: data duplicated when msgdispatcher make splitting (#42827)

issue: #41570

Signed-off-by: chyezh <chyezh@outlook.com>

internal/datacoord/garbage_collector.go

@@ -415,7 +415,6 @@ func (gc *garbageCollector) checkDroppedSegmentGC(segment *SegmentInfo,
 
 // recycleDroppedSegments scans all segments and remove those dropped segments from meta and oss.
 func (gc *garbageCollector) recycleDroppedSegments(ctx context.Context) {
-
 	start := time.Now()
 	log := log.With(zap.String("gcName", "recycleDroppedSegments"), zap.Time("startAt", start))
 	log.Info("start clear dropped segments...")

internal/datanode/services.go

@@ -22,6 +22,7 @@ package datanode
 import (
 	"context"
 	"fmt"
+
 	"github.com/samber/lo"
 	"go.uber.org/zap"
 	"google.golang.org/protobuf/proto"

pkg/mq/msgdispatcher/dispatcher_test.go

@@ -81,7 +81,7 @@ func TestDispatcher(t *testing.T) {
 			target := newTarget(&StreamConfig{
 				VChannel: vchannel,
 				Pos:      pos,
-			})
+			}, false)
 			target.ch = ch
 			return target
 		}
@@ -104,7 +104,7 @@ func TestDispatcher(t *testing.T) {
 	t.Run("test concurrent send and close", func(t *testing.T) {
 		for i := 0; i < 100; i++ {
 			output := make(chan *msgstream.MsgPack, 1024)
-			target := newTarget(&StreamConfig{VChannel: "mock_vchannel_0"})
+			target := newTarget(&StreamConfig{VChannel: "mock_vchannel_0"}, false)
 			target.ch = output
 			assert.Equal(t, cap(output), cap(target.ch))
 			wg := &sync.WaitGroup{}
@@ -145,11 +145,11 @@ func TestGroupMessage(t *testing.T) {
 	d, err := NewDispatcher(context.Background(), newMockFactory(), time.Now().UnixNano(), "mock_pchannel_0",
 		nil, common.SubscriptionPositionEarliest, false, 0, false)
 	assert.NoError(t, err)
-	d.AddTarget(newTarget(&StreamConfig{VChannel: "mock_pchannel_0_1v0"}))
+	d.AddTarget(newTarget(&StreamConfig{VChannel: "mock_pchannel_0_1v0"}, false))
 	d.AddTarget(newTarget(&StreamConfig{
 		VChannel:        "mock_pchannel_0_2v0",
 		ReplicateConfig: msgstream.GetReplicateConfig("local-test", "foo", "coo"),
-	}))
+	}, false))
 	{
 		// no replicate msg
 		packs := d.groupAndParseMsgs(msgstream.BuildConsumeMsgPack(&MsgPack{

pkg/mq/msgdispatcher/manager.go

@@ -84,7 +84,7 @@ func NewDispatcherManager(pchannel string, role string, nodeID int64, factory ms
 }
 
 func (c *dispatcherManager) Add(ctx context.Context, streamConfig *StreamConfig) (<-chan *MsgPack, error) {
-	t := newTarget(streamConfig)
+	t := newTarget(streamConfig, c.includeSkipWhenSplit)
 	if _, ok := c.registeredTargets.GetOrInsert(t.vchannel, t); ok {
 		return nil, fmt.Errorf("vchannel %s already exists in the dispatcher", t.vchannel)
 	}

pkg/mq/msgdispatcher/target.go

@@ -30,11 +30,13 @@ import (
 )
 
 type target struct {
-	vchannel string
+	vchannel           string
-	ch       chan *MsgPack
+	ch                 chan *MsgPack
-	subPos   SubPos
+	subPos             SubPos
-	pos      *Pos
+	pos                *Pos
-	isLagged bool
+	filterSameTimeTick bool
+	latestTimeTick     uint64
+	isLagged           bool
 
 	closeMu         sync.Mutex
 	closeOnce       sync.Once
@@ -46,18 +48,20 @@ type target struct {
 	cancelCh lifetime.SafeChan
 }
 
-func newTarget(streamConfig *StreamConfig) *target {
+func newTarget(streamConfig *StreamConfig, filterSameTimeTick bool) *target {
 	replicateConfig := streamConfig.ReplicateConfig
 	maxTolerantLag := paramtable.Get().MQCfg.MaxTolerantLag.GetAsDuration(time.Second)
 	t := &target{
-		vchannel:        streamConfig.VChannel,
+		vchannel:           streamConfig.VChannel,
-		ch:              make(chan *MsgPack, paramtable.Get().MQCfg.TargetBufSize.GetAsInt()),
+		ch:                 make(chan *MsgPack, paramtable.Get().MQCfg.TargetBufSize.GetAsInt()),
-		subPos:          streamConfig.SubPos,
+		subPos:             streamConfig.SubPos,
-		pos:             streamConfig.Pos,
+		pos:                streamConfig.Pos,
-		cancelCh:        lifetime.NewSafeChan(),
+		filterSameTimeTick: filterSameTimeTick,
-		maxLag:          maxTolerantLag,
+		latestTimeTick:     0,
-		timer:           time.NewTimer(maxTolerantLag),
+		cancelCh:           lifetime.NewSafeChan(),
-		replicateConfig: replicateConfig,
+		maxLag:             maxTolerantLag,
+		timer:              time.NewTimer(maxTolerantLag),
+		replicateConfig:    replicateConfig,
 	}
 	t.closed = false
 	if replicateConfig != nil {
@@ -87,6 +91,23 @@ func (t *target) send(pack *MsgPack) error {
 		return nil
 	}
 
+	if t.filterSameTimeTick {
+		if pack.EndPositions[0].GetTimestamp() <= t.latestTimeTick {
+			if len(pack.Msgs) > 0 {
+				// only filter out the msg that is only timetick message,
+				// So it's a unexpected behavior if the msgs is not empty
+				log.Warn("some data lost when time tick filtering",
+					zap.String("vchannel", t.vchannel),
+					zap.Uint64("latestTimeTick", t.latestTimeTick),
+					zap.Uint64("packEndTs", pack.EndPositions[0].GetTimestamp()),
+					zap.Int("msgCount", len(pack.Msgs)),
+				)
+			}
+			// filter out the msg that is already sent with the same timetick.
+			return nil
+		}
+	}
+
 	if !t.timer.Stop() {
 		select {
 		case <-t.timer.C:
@@ -100,8 +121,11 @@ func (t *target) send(pack *MsgPack) error {
 		return nil
 	case <-t.timer.C:
 		t.isLagged = true
-		return fmt.Errorf("send target timeout, vchannel=%s, timeout=%s, beginTs=%d, endTs=%d", t.vchannel, t.maxLag, pack.BeginTs, pack.EndTs)
+		return fmt.Errorf("send target timeout, vchannel=%s, timeout=%s, beginTs=%d, endTs=%d, latestTimeTick=%d", t.vchannel, t.maxLag, pack.BeginTs, pack.EndTs, t.latestTimeTick)
 	case t.ch <- pack:
+		if len(pack.EndPositions) > 0 {
+			t.latestTimeTick = pack.EndPositions[0].GetTimestamp()
+		}
 		return nil
 	}
 }

pkg/mq/msgdispatcher/target_test.go

@@ -17,7 +17,7 @@ func TestSendTimeout(t *testing.T) {
 	target := newTarget(&StreamConfig{
 		VChannel: "test1",
 		Pos:      &msgpb.MsgPosition{},
-	})
+	}, false)
 
 	time.Sleep(paramtable.Get().MQCfg.MaxTolerantLag.GetAsDuration(time.Second))
 
@@ -31,3 +31,25 @@ func TestSendTimeout(t *testing.T) {
 	}
 	assert.Equal(t, counter, 0)
 }
+
+func TestSendTimeTickFiltering(t *testing.T) {
+	target := newTarget(&StreamConfig{
+		VChannel: "test1",
+		Pos:      &msgpb.MsgPosition{},
+	}, true)
+	target.send(&msgstream.MsgPack{
+		EndPositions: []*msgpb.MsgPosition{
+			{
+				Timestamp: 1,
+			},
+		},
+	})
+
+	target.send(&msgstream.MsgPack{
+		EndPositions: []*msgpb.MsgPosition{
+			{
+				Timestamp: 1,
+			},
+		},
+	})
+}