Prevent datacoord from syncing unflushed segments (#19659)

See also: #19653

Signed-off-by: yangxuan <xuan.yang@zilliz.com>

Signed-off-by: yangxuan <xuan.yang@zilliz.com>

internal/datanode/segment_replica.go

@@ -768,7 +768,8 @@ func (replica *SegmentReplica) mergeFlushedSegments(seg *Segment, planID UniqueI
 
 	var inValidSegments []UniqueID
 	for _, ID := range compactedFrom {
-		if !replica.hasSegment(ID, true) {
+		// no such segments in replica or the segments are unflushed.
+		if !replica.hasSegment(ID, true) || replica.hasSegment(ID, false) {
 			inValidSegments = append(inValidSegments, ID)
 		}
 	}

internal/datanode/segment_replica_test.go

@@ -838,6 +838,11 @@ func TestSegmentReplica_InterfaceMethod(t *testing.T) {
 				collectionID: 1,
 				numRows:      15,
 			}},
+			{"segment exists but not flushed", false, false, []UniqueID{1, 4}, &Segment{
+				segmentID:    3,
+				collectionID: 1,
+				numRows:      15,
+			}},
 		}
 
 		for _, test := range tests {
@@ -851,12 +856,23 @@ func TestSegmentReplica_InterfaceMethod(t *testing.T) {
 					sr.addFlushedSegmentWithPKs(2, 1, 0, "channel", 10, primaryKeyData)
 				}
 
+				if !sr.hasSegment(4, false) {
+					sr.removeSegments(4)
+					sr.addSegment(addSegmentReq{
+						segType:     datapb.SegmentType_Normal,
+						segID:       4,
+						collID:      1,
+						partitionID: 0,
+					})
+				}
+
 				if sr.hasSegment(3, true) {
 					sr.removeSegments(3)
 				}
 
 				require.True(t, sr.hasSegment(1, true))
 				require.True(t, sr.hasSegment(2, true))
+				require.True(t, sr.hasSegment(4, false))
 				require.False(t, sr.hasSegment(3, true))
 
 				// tests start