pitr task can't pause after flashback

[seiya-annie]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

1. flashback test env
2. pause pitr task and execute flashback ddl; then resume pitr task
3. run workload
4. try to pause pitr task

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

pause success

3. What did you see instead (Required)

[root@localhost ~]# tiup br log pause --task-name=pitr
tiup is checking updates for component br ...
Starting component br: /root/.tiup/components/br/v6.3.0/br log pause --task-name=pitr
Detail BR log in /tmp/br.log.2022-11-01T10.16.21+0800
[2022/11/01 10:16:23.339 +08:00] [INFO] [collector.go:69] ["log pause failed summary"] [total-ranges=1] [ranges-succeed=0] [ranges-failed=1] [unit-name="log pause"] [error="failed to check gc safePoint, ts 437053100866404357: GC safepoint 437062349728776192 exceed TS 437053100866404357: [BR:Backup:ErrBackupGCSafepointExceeded]backup GC safepoint exceeded"] [errorVerbose="[BR:Backup:ErrBackupGCSafepointExceeded]backup GC safepoint exceeded\nGC safepoint 437062349728776192 exceed TS 437053100866404357\ngithub.com/pingcap/tidb/br/pkg/utils.CheckGCSafePoint\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/br/br/pkg/utils/safe_point.go:76\ngithub.com/pingcap/tidb/br/pkg/task.(*streamMgr).setGCSafePoint\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/br/br/pkg/task/stream.go:370\ngithub.com/pingcap/tidb/br/pkg/task.RunStreamPause\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/br/br/pkg/task/stream.go:687\ngithub.com/pingcap/tidb/br/pkg/task.RunStreamCommand\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/br/br/pkg/task/stream.go:455\nmain.streamCommand\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/br/br/cmd/br/stream.go:231\nmain.newStreamPauseCommand.func1\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/br/br/cmd/br/stream.go:100\ngithub.com/spf13/cobra.(*Command).execute\n\t/go/pkg/mod/github.com/spf13/cobra@v1.5.0/command.go:872\ngithub.com/spf13/cobra.(*Command).ExecuteC\n\t/go/pkg/mod/github.com/spf13/cobra@v1.5.0/command.go:990\ngithub.com/spf13/cobra.(*Command).Execute\n\t/go/pkg/mod/github.com/spf13/cobra@v1.5.0/command.go:918\nmain.main\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/br/br/cmd/br/main.go:57\nruntime.main\n\t/usr/local/go/src/runtime/proc.go:250\nruntime.goexit\n\t/usr/local/go/src/runtime/asm_amd64.s:1594\nfailed to check gc safePoint, ts 437053100866404357"]
Error: failed to check gc safePoint, ts 437053100866404357: GC safepoint 437062349728776192 exceed TS 437053100866404357: [BR:Backup:ErrBackupGCSafepointExceeded]backup GC safepoint exceeded

[root@localhost ~]# tiup br log metadata -s "s3://tmp/br-lt-log-backup?access-key=minioadmin&secret-access-key=minioadmin&endpoint=http%3a%2f%2fminio.pingcap.net%3a9000&force-path-style=true"
tiup is checking updates for component br ...
Starting component br: /root/.tiup/components/br/v6.3.0/br log metadata -s s3://tmp/br-lt-log-backup?access-key=minioadmin&secret-access-key=minioadmin&endpoint=http%3a%2f%2fminio.pingcap.net%3a9000&force-path-style=true
Detail BR log in /tmp/br.log.2022-11-01T10.02.27+0800
[2022/11/01 10:02:27.325 +08:00] [INFO] [collector.go:69] ["log metadata"] [log-min-ts=437053100866404358] [log-min-date="2022-10-31 22:07:48.808 +0800"] [log-max-ts=437064312178081795] [log-max-date="2022-11-01 10:00:36.568 +0800"]
[2022/11/01 10:02:27.325 +08:00] [INFO] [collector.go:69] ["log metadata success summary"] [total-ranges=0] [ranges-succeed=0] [ranges-failed=0] [total-take=275.940924ms]

4. What is your TiDB version? (Required)

[root@localhost ~]# /data1/tidb-deploy/tidb-4000/bin/tidb-server -V
Release Version: v6.4.0-alpha
Edition: Community
Git Commit Hash: e415cfa
Git Branch: heads/refs/tags/v6.4.0-alpha
UTC Build Time: 2022-10-28 14:35:26
GoVersion: go1.19.1
Race Enabled: false
TiKV Min Version: 6.2.0-alpha
Check Table Before Drop: false
Store: unistore
[root@localhost ~]#