diff --git a/internal/datanode/flow_graph_insert_buffer_node.go b/internal/datanode/flow_graph_insert_buffer_node.go
index cf83cedafb..0f1fef4de9 100644
--- a/internal/datanode/flow_graph_insert_buffer_node.go
+++ b/internal/datanode/flow_graph_insert_buffer_node.go
@@ -126,12 +126,14 @@ func (ibNode *insertBufferNode) Operate(in []Msg) []Msg {
 		pos.ChannelName = ibNode.channelName
 		startPositions = append(startPositions, pos)
 	}
+	fgMsg.startPositions = startPositions
 	endPositions := make([]*internalpb.MsgPosition, 0, len(fgMsg.endPositions))
 	for idx := range fgMsg.endPositions {
 		pos := proto.Clone(fgMsg.endPositions[idx]).(*internalpb.MsgPosition)
 		pos.ChannelName = ibNode.channelName
 		endPositions = append(endPositions, pos)
 	}
+	fgMsg.endPositions = endPositions
 
 	if startPositions[0].Timestamp < ibNode.lastTimestamp {
 		// message stream should guarantee that this should not happen