diff --git a/downstreamadapter/dispatcher/table_progress.go b/downstreamadapter/dispatcher/table_progress.go
index 6c132c57f..9f9972bd2 100644
--- a/downstreamadapter/dispatcher/table_progress.go
+++ b/downstreamadapter/dispatcher/table_progress.go
@@ -132,5 +132,11 @@ func (p *TableProgress) GetEventSizePerSecond() float32 {
 	p.cumulateEventSize = 0
 	p.lastQueryTime = time.Now()
 
+	if eventSizePerSecond == 0 {
+		// The event size will only send to maintainer once per second.
+		// So if no data is write, we use a tiny value instead of 0 to distinguish it from the status without eventSize
+		return 0.1
+	}
+
 	return eventSizePerSecond
 }
diff --git a/maintainer/replica/checker.go b/maintainer/replica/checker.go
index d1c48a676..76c67e67a 100644
--- a/maintainer/replica/checker.go
+++ b/maintainer/replica/checker.go
@@ -47,7 +47,7 @@ const (
 	clearTimeout                  = 300           // seconds
 )
 
-var MinSpanNumberCoefficient = 2
+var MinSpanNumberCoefficient = 32 // // This number is twice the default worker count of the MySQL sink. It can help evenly split and dispatch high - throughput tables.
 
 type CheckResult struct {
 	OpType       OpType
@@ -127,7 +127,9 @@ func (s *hotSpanChecker) UpdateStatus(span *SpanReplication) {
 		return
 	}
 
-	if status.EventSizePerSecond < s.writeThreshold {
+	log.Debug("hotSpanChecker EventSizePerSecond", zap.Any("span", span.Span), zap.Any("dispatcher", span.ID), zap.Any("EventSizePerSecond", status.EventSizePerSecond), zap.Any("writeThreshold", s.writeThreshold))
+
+	if status.EventSizePerSecond != 0 && status.EventSizePerSecond < s.writeThreshold {
 		if hotSpan, ok := s.hotTasks[span.ID]; ok {
 			hotSpan.score--
 			if hotSpan.score == 0 {
@@ -154,6 +156,7 @@ func (s *hotSpanChecker) Check(batchSize int) replica.GroupCheckResult {
 	cache := make([]CheckResult, 0)
 
 	for _, hotSpan := range s.hotTasks {
+		log.Debug("hot span", zap.String("changefeed", s.changefeedID.Name()), zap.String("span", hotSpan.ID.String()), zap.Int("score", hotSpan.score), zap.Int("scoreThreshold", s.scoreThreshold))
 		if time.Since(hotSpan.lastUpdateTime) > clearTimeout*time.Second {
 			// should not happen
 			log.Panic("remove hot span since it is outdated",
diff --git a/maintainer/split/region_count_splitter.go b/maintainer/split/region_count_splitter.go
index f18de5a83..6326a853c 100644
--- a/maintainer/split/region_count_splitter.go
+++ b/maintainer/split/region_count_splitter.go
@@ -154,7 +154,7 @@ func newEvenlySplitStepper(pages int, totalRegion int) evenlySplitStepper {
 		extraRegionPerSpan: extraRegionPerSpan,
 		remain:             remain,
 	}
-	log.Info("evenly split stepper", zap.Any("evenlySplitStepper", res))
+	log.Info("evenly split stepper", zap.Any("regionPerSpan", regionPerSpan), zap.Any("spanCount", pages), zap.Any("extraRegionPerSpan", extraRegionPerSpan))
 	return res
 }
 
diff --git a/maintainer/split/region_count_splitter_test.go b/maintainer/split/region_count_splitter_test.go
index ad1bbe277..8102464b9 100644
--- a/maintainer/split/region_count_splitter_test.go
+++ b/maintainer/split/region_count_splitter_test.go
@@ -29,7 +29,13 @@ import (
 )
 
 func TestRegionCountSplitSpan(t *testing.T) {
-	t.Parallel()
+	// t.Parallel()
+
+	oldBaseSpanNumberCoefficient := baseSpanNumberCoefficient
+	baseSpanNumberCoefficient = 3
+	defer func() {
+		baseSpanNumberCoefficient = oldBaseSpanNumberCoefficient
+	}()
 
 	cache := NewMockRegionCache(nil)
 	cache.regions.ReplaceOrInsert(tablepb.Span{StartKey: []byte("t1_0"), EndKey: []byte("t1_1")}, 1)
@@ -134,7 +140,13 @@ func TestRegionCountSplitSpan(t *testing.T) {
 }
 
 func TestRegionCountEvenlySplitSpan(t *testing.T) {
-	t.Parallel()
+	// t.Parallel()
+
+	oldBaseSpanNumberCoefficient := baseSpanNumberCoefficient
+	baseSpanNumberCoefficient = 3
+	defer func() {
+		baseSpanNumberCoefficient = oldBaseSpanNumberCoefficient
+	}()
 
 	cache := NewMockRegionCache(nil)
 	totalRegion := 1000
diff --git a/maintainer/split/write_bytes_splitter.go b/maintainer/split/write_bytes_splitter.go
index 11671fe0f..4f8027add 100644
--- a/maintainer/split/write_bytes_splitter.go
+++ b/maintainer/split/write_bytes_splitter.go
@@ -83,6 +83,10 @@ func (m *writeSplitter) split(
 			zap.String("namespace", m.changefeedID.Namespace()),
 			zap.String("changefeed", m.changefeedID.Name()),
 			zap.String("span", span.String()),
+			zap.Int("captureNum", captureNum),
+			zap.Int("expectedSpanNum", expectedSpanNum),
+			zap.Int("DefaultMaxSpanNumber", DefaultMaxSpanNumber),
+			zap.Int("regionsLen", len(regions)),
 			zap.Error(err))
 		return []*heartbeatpb.TableSpan{span}
 	}
@@ -139,6 +143,7 @@ func (m *writeSplitter) splitRegionsByWrittenKeysV1(
 	// 1. If the total write is less than writeKeyThreshold
 	// don't need to split the regions
 	if totalWrite < uint64(m.writeKeyThreshold) {
+		log.Info("total write less than writeKeyThreshold, skip split", zap.Any("totalWrite", totalWrite), zap.Any("writeKeyThreshold", m.writeKeyThreshold))
 		return &splitRegionsInfo{
 			RegionCounts: []int{len(regions)},
 			Weights:      []uint64{totalWriteNormalized},
diff --git a/maintainer/split/write_bytes_splitter_test.go b/maintainer/split/write_bytes_splitter_test.go
index b089edb1a..f205629be 100644
--- a/maintainer/split/write_bytes_splitter_test.go
+++ b/maintainer/split/write_bytes_splitter_test.go
@@ -169,7 +169,12 @@ func TestSplitRegionsByWrittenKeysHotspot2(t *testing.T) {
 }
 
 func TestSplitRegionsByWrittenKeysCold(t *testing.T) {
-	t.Parallel()
+	// t.Parallel()
+	oldBaseSpanNumberCoefficient := baseSpanNumberCoefficient
+	baseSpanNumberCoefficient = 3
+	defer func() {
+		baseSpanNumberCoefficient = oldBaseSpanNumberCoefficient
+	}()
 	re := require.New(t)
 	cfID := common.NewChangeFeedIDWithName("test")
 	splitter := newWriteSplitter(cfID, nil, 0)
@@ -195,7 +200,12 @@ func TestSplitRegionsByWrittenKeysCold(t *testing.T) {
 }
 
 func TestNotSplitRegionsByWrittenKeysCold(t *testing.T) {
-	t.Parallel()
+	// t.Parallel()
+	oldBaseSpanNumberCoefficient := baseSpanNumberCoefficient
+	baseSpanNumberCoefficient = 3
+	defer func() {
+		baseSpanNumberCoefficient = oldBaseSpanNumberCoefficient
+	}()
 	re := require.New(t)
 	cfID := common.NewChangeFeedIDWithName("test")
 	splitter := newWriteSplitter(cfID, nil, 1)