Can not get the gc safepoint from PD for new deployed cluster

[JaySon-Huang]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

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

3. What did you see instead (Required)

There are many gc safepoint == 0 logging for new deploy cluster

[2023-11-12T01:18:34.253Z] [2023/11/12 01:18:33.890 +00:00] [INFO] [SchemaSyncService.cpp:193] ["Schema GC begin, last_safepoint=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.253Z] [2023/11/12 01:18:33.890 +00:00] [INFO] [SchemaSyncService.cpp:358] ["Schema GC done, tables_removed=0 databases_removed=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.253Z] [2023/11/12 01:18:33.890 +00:00] [INFO] [SchemaSyncService.cpp:193] ["Schema GC begin, last_safepoint=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.253Z] [2023/11/12 01:18:33.890 +00:00] [INFO] [SchemaSyncService.cpp:358] ["Schema GC done, tables_removed=0 databases_removed=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.891 +00:00] [INFO] [SchemaSyncService.cpp:193] ["Schema GC begin, last_safepoint=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.891 +00:00] [INFO] [SchemaSyncService.cpp:358] ["Schema GC done, tables_removed=0 databases_removed=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.891 +00:00] [INFO] [SchemaSyncService.cpp:193] ["Schema GC begin, last_safepoint=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.891 +00:00] [INFO] [SchemaSyncService.cpp:358] ["Schema GC done, tables_removed=0 databases_removed=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.892 +00:00] [INFO] [SchemaSyncService.cpp:193] ["Schema GC begin, last_safepoint=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.892 +00:00] [INFO] [SchemaSyncService.cpp:358] ["Schema GC done, tables_removed=0 databases_removed=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.892 +00:00] [INFO] [SchemaSyncService.cpp:193] ["Schema GC begin, last_safepoint=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.892 +00:00] [INFO] [SchemaSyncService.cpp:358] ["Schema GC done, tables_removed=0 databases_removed=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.893 +00:00] [INFO] [SchemaSyncService.cpp:193] ["Schema GC begin, last_safepoint=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.893 +00:00] [INFO] [SchemaSyncService.cpp:358] ["Schema GC done, tables_removed=0 databases_removed=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.893 +00:00] [INFO] [SchemaSyncService.cpp:193] ["Schema GC begin, last_safepoint=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]
[2023-11-12T01:18:34.254Z] [2023/11/12 01:18:33.893 +00:00] [INFO] [SchemaSyncService.cpp:358] ["Schema GC done, tables_removed=0 databases_removed=0 safepoint=0"] [source="keyspace=4294967295"] [thread_id=84]

4. What is your TiFlash version? (Required)

master

[JaySon-Huang]

After a new tidb cluster deployed, there is an interval that PD will return gc safepoint with 0

>  tiup ctl:nightly pd -u [10.2.12.81:6540](http://10.2.12.81:6540/) -i
Starting component `ctl`: /DATA/disk1/ra_common/.tiup/components/ctl/v7.6.0-alpha-nightly-20231112/ctl pd -u [10.2.12.81:6540](http://10.2.12.81:6540/) -i
» service-gc-safepoint
{
  "service_gc_safe_points": [
    {
      "service_id": "gc_worker",
      "expired_at": 9223372036854775807,
      "safe_point": 445603590956646400
    }
  ],
  "gc_safe_point": 0 <-- tiflash use this value
}

This will lead to SchemaSyncService::gc running repeatedly. This results in lots of useless logging and getting gc safepoint from pd frequently.