diff --git a/configs/milvus.yaml b/configs/milvus.yaml
index 98609675ca..c737f4df96 100644
--- a/configs/milvus.yaml
+++ b/configs/milvus.yaml
@@ -283,6 +283,7 @@ dataCoord:
     # (smallProportion * segment max # of rows).
     compactableProportion: 0.5 # A compaction will happen on small segments if the segment after compaction will have
     # over (compactableProportion * segment max # of rows) rows.
+    # MUST BE GREATER THAN OR EQUAL TO <smallProportion>!!!
 
   compaction:
     enableAutoCompaction: true
diff --git a/internal/datacoord/compaction_trigger.go b/internal/datacoord/compaction_trigger.go
index 7b9127e278..e011bcb51a 100644
--- a/internal/datacoord/compaction_trigger.go
+++ b/internal/datacoord/compaction_trigger.go
@@ -535,7 +535,9 @@ func (t *compactionTrigger) generatePlans(segments []*SegmentInfo, force bool, i
 			targetRow += s.GetNumOfRows()
 		}
 		// only merge if candidate number is large than MinSegmentToMerge or if target row is large enough
-		if len(bucket) >= Params.DataCoordCfg.MinSegmentToMerge || targetRow > int64(float64(segment.GetMaxRowNum())*Params.DataCoordCfg.SegmentCompactableProportion) {
+		if len(bucket) >= Params.DataCoordCfg.MinSegmentToMerge ||
+			len(bucket) > 1 &&
+				targetRow > int64(float64(segment.GetMaxRowNum())*Params.DataCoordCfg.SegmentCompactableProportion) {
 			plan := segmentsToPlan(bucket, compactTime)
 			log.Info("generate a plan for small candidates", zap.Any("plan", plan),
 				zap.Int64("target segment row", targetRow), zap.Int64("target segment size", size))