System table restore failed

[XuJianxu]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

• Execute full backup.
• Execute full restore.
• Check the system table.

2. What did you expect to see? (Required)

System table will restore success.

3. What did you see instead (Required)

System table haven't restore

4. What is your TiDB version? (Required)

v5.3.0

[joccau]

The reason of fail to restore system table is that the schema name is incorrect during backup， which is caused by concurrent operation of "add temporary-prefix into system schema name".

[2021/11/12 14:30:15.438 +08:00] [INFO] [validate.go:78] ["checksum success"] [db=__TiDB_BR_Temporary___TiDB_BR_Temporary___TiDB_BR_Temporary_mysql] [table=capture_plan_baselines_blacklist] [2021/11/12 14:30:15.438 +08:00] [INFO] [validate.go:78] ["checksum success"] [db=__TiDB_BR_Temporary___TiDB_BR_Temporary___TiDB_BR_Temporary_mysql] [table=stats_fm_sketch] [2021/11/12 14:30:15.438 +08:00] [INFO] [validate.go:78] ["checksum success"] [db=__TiDB_BR_Temporary___TiDB_BR_Temporary___TiDB_BR_Temporary_mysql] [table=tidb]

[github-actions]

Please check whether the issue should be labeled with 'affects-x.y' or 'fixes-x.y.z', and then remove 'needs-more-info' label.