ntp时钟同步异常（提前、落后）对集群运行有何影响？直接修复到当前时刻有何风险？

🪐 TiDB 技术问题
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14

时间回调虽然不会导致TSO回退，但是还是有可能引发一些逻辑问题，比如下面的实验，我将时间手工调整到2024年1月22日（实验当天正确时间为2024年1月14日），然后再回调回来，发现TSO时间大幅增加后，再做快照备份就出错了。
参考实验

MySQL [(none)]> SELECT TIDB_PARSE_TSO(447201033313058816);
+------------------------------------+
| TIDB_PARSE_TSO(447201033313058816) |
+------------------------------------+
| 2024-01-22 23:15:58.964000         |
+------------------------------------+
1 row in set (0.00 sec)

MySQL [(none)]> exit
Bye
[root@localhost ~]# date
Sun Jan 14 22:53:16 CST 2024
[root@localhost ~]# tiup br backup full \
>     --pd "192.168.0.100:2379" \
>     --backupts '2024-01-14 22:46:00' \
>     --storage "local:///tmp/backup5" \
>     --ratelimit 128 \
>     --log-file backupfull20240114.log
tiup is checking updates for component br ...
Starting component `br`: /root/.tiup/components/br/v7.5.0/br backup full --pd 192.168.0.100:2379 --backupts 2024-01-14 22:46:00 --storage local:///tmp/backup5 --ratelimit 128 --log-file backupfull20240114.log

Detail BR log in backupfull20240114.log 
[2024/01/14 22:53:41.761 +08:00] [WARN] [backup.go:312] ["setting `--ratelimit` and `--concurrency` at the same time, ignoring `--concurrency`: `--ratelimit` forces sequential (i.e. concurrency = 1) backup"] [ratelimit=134.2MB/s] [concurrency-specified=4]
[2024/01/14 22:53:46.255 +08:00] [INFO] [collector.go:77] ["Full Backup failed summary"] [total-ranges=0] [ranges-succeed=0] [ranges-failed=0]
Error: GC safepoint 447201033313058816 exceed TS 447019367792640000: [BR:Backup:ErrBackupGCSafepointExceeded]backup GC safepoint exceeded
[root@localhost ~]#
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