TiCDC同步进度停滞，sorter文件剧增

昨天的query查看状态是normal，cdc.log一直在刷Unified Sorter: trying to create file backEnd，现在changefeed已经faild了，报这个
“message”: “[CDC:ErrGCTTLExceeded]the checkpoint-ts(436308863790350610) lag of the changefeed(simple-replication-task) has exceeded the GC TTL”