Change SeekPosition to earliest of all segments (#10771)

Signed-off-by: NCongqi Xia <congqi.xia@zilliz.com>

internal/datacoord/channel_manager.go

@@ -250,7 +250,7 @@ func (c *ChannelManager) Watch(ch *channel) error {
 
 func (c *ChannelManager) fillChannelPosition(update *ChannelOp) {
 	for _, ch := range update.Channels {
-		vchan := c.posProvider.GetVChanPositions(ch.Name, ch.CollectionID, true)
+		vchan := c.posProvider.GetVChanPositions(ch.Name, ch.CollectionID, false)
 		info := &datapb.ChannelWatchInfo{
 			Vchan:   vchan,
 			StartTs: time.Now().Unix(),

internal/datacoord/server.go

@@ -683,29 +683,30 @@ func (s *Server) GetVChanPositions(channel string, collectionID UniqueID, seekFr
 	flushed := make([]*datapb.SegmentInfo, 0)
 	unflushed := make([]*datapb.SegmentInfo, 0)
 	var seekPosition *internalpb.MsgPosition
-	var useUnflushedPosition bool
 	for _, s := range segments {
 		if s.State == commonpb.SegmentState_Flushing || s.State == commonpb.SegmentState_Flushed {
 			flushed = append(flushed, trimSegmentInfo(s.SegmentInfo))
-			if seekPosition == nil || (!useUnflushedPosition && s.DmlPosition.Timestamp > seekPosition.Timestamp) {
+			if seekPosition == nil || (s.DmlPosition.Timestamp < seekPosition.Timestamp) {
 				seekPosition = s.DmlPosition
 			}
 			continue
 		}
 
-		if s.DmlPosition == nil {
+		if s.DmlPosition == nil { // segment position all nil
 			continue
 		}
 
 		unflushed = append(unflushed, trimSegmentInfo(s.SegmentInfo))
 
-		if seekPosition == nil || !useUnflushedPosition || s.DmlPosition.Timestamp < seekPosition.Timestamp {
-			useUnflushedPosition = true
-			if !seekFromStartPosition {
-				seekPosition = s.DmlPosition
-			} else {
-				seekPosition = s.StartPosition
-			}
+		segmentPosition := s.DmlPosition
+		if seekFromStartPosition {
+			// need to use start position when load collection/partition, querynode does not support seek from checkpoint yet
+			// TODO silverxia remove seek from start logic after checkpoint supported in querynode
+			segmentPosition = s.StartPosition
+		}
+
+		if seekPosition == nil || segmentPosition.Timestamp < seekPosition.Timestamp {
+			seekPosition = segmentPosition
 		}
 	}
 	// use collection start position when segment position is not found

internal/datacoord/server_test.go

@@ -1179,7 +1179,7 @@ func TestGetRecoveryInfo(t *testing.T) {
 		}
 	}
 
-	t.Run("test get largest position of flushed segments as seek position", func(t *testing.T) {
+	t.Run("test get earliest position of flushed segments as seek position", func(t *testing.T) {
 		svr := newTestServer(t, nil)
 		defer closeTestServer(t, svr)
 
@@ -1204,7 +1204,7 @@ func TestGetRecoveryInfo(t *testing.T) {
 		assert.EqualValues(t, 1, len(resp.GetChannels()))
 		assert.EqualValues(t, 0, len(resp.GetChannels()[0].GetUnflushedSegments()))
 		assert.ElementsMatch(t, []*datapb.SegmentInfo{trimSegmentInfo(seg1), trimSegmentInfo(seg2)}, resp.GetChannels()[0].GetFlushedSegments())
-		assert.EqualValues(t, 20, resp.GetChannels()[0].GetSeekPosition().GetTimestamp())
+		assert.EqualValues(t, 10, resp.GetChannels()[0].GetSeekPosition().GetTimestamp())
 	})
 
 	t.Run("test get recovery of unflushed segments ", func(t *testing.T) {
@@ -1232,6 +1232,7 @@ func TestGetRecoveryInfo(t *testing.T) {
 		assert.EqualValues(t, 0, len(resp.GetBinlogs()))
 		assert.EqualValues(t, 1, len(resp.GetChannels()))
 		assert.NotNil(t, resp.GetChannels()[0].SeekPosition)
+		assert.EqualValues(t, 0, resp.GetChannels()[0].GetSeekPosition().GetTimestamp())
 	})
 
 	t.Run("test get binlogs", func(t *testing.T) {

internal/datacoord/services.go

@@ -476,7 +476,7 @@ func (s *Server) GetRecoveryInfo(ctx context.Context, req *datapb.GetRecoveryInf
 	channels := dresp.GetVirtualChannelNames()
 	channelInfos := make([]*datapb.VchannelInfo, 0, len(channels))
 	for _, c := range channels {
-		channelInfo := s.GetVChanPositions(c, collectionID, false)
+		channelInfo := s.GetVChanPositions(c, collectionID, true)
 		channelInfos = append(channelInfos, channelInfo)
 	}