Add default timestamp when send statistics of pchan (#5854)

Signed-off-by: dragondriver <jiquan.long@zilliz.com>

internal/proxynode/proxy_node.go

@@ -281,6 +281,12 @@ func (node *ProxyNode) sendChannelsTimeTickLoop() {
 			case <-node.ctx.Done():
 				return
 			case <-timer.C:
+				ts, err := node.tsoAllocator.AllocOne()
+				if err != nil {
+					log.Warn("Failed to get timestamp from tso", zap.Error(err))
+					continue
+				}
+
 				stats, err := node.chTicker.getMinTsStatistics()
 				if err != nil {
 					log.Warn("sendChannelsTimeTickLoop.getMinTsStatistics", zap.Error(err))
@@ -290,10 +296,15 @@ func (node *ProxyNode) sendChannelsTimeTickLoop() {
 				channels := make([]pChan, 0, len(stats))
 				tss := make([]Timestamp, 0, len(stats))
 
+				maxTs := ts
 				for channel, ts := range stats {
 					channels = append(channels, channel)
 					tss = append(tss, ts)
+					if ts > maxTs {
+						maxTs = ts
+					}
 				}
+
 				log.Debug("send timestamp statistics of pchan", zap.Any("channels", channels), zap.Any("tss", tss))
 
 				req := &internalpb.ChannelTimeTickMsg{
@@ -303,8 +314,9 @@ func (node *ProxyNode) sendChannelsTimeTickLoop() {
 						Timestamp: 0,                         // todo
 						SourceID:  node.session.ServerID,
 					},
-					ChannelNames: channels,
-					Timestamps:   tss,
+					ChannelNames:     channels,
+					Timestamps:       tss,
+					DefaultTimestamp: maxTs,
 				}
 
 				status, err := node.masterService.UpdateChannelTimeTick(node.ctx, req)