The IS_LEARNER field data in the TIKV_REGION_PEERS table is incorrect

[HunDunDM]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

• Randomly choose a Region containing Learner peer (commonly found in the cluster containing TiFlash)
• pd-ctl region ${region_id}
• SELECT * FROM INFORMATION_SCHEMA.TIKV_REGION_PEERS WHERE REGION_ID=${region_id};

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

• Their data should be consistent.

3. What did you see instead (Required)

• Peer 104792 is a Learner but not in the SQL results.

region 83693
{
  "id": 83693,
  "start_key": "7480000000000000FF465F728000000000FF0555BF0000000000FA",
  "end_key": "7480000000000000FF465F728000000000FF06E05F0000000000FA",
  "epoch": {
    "conf_ver": 20,
    "version": 4516
  },
  "peers": [
    {
      "id": 83694,
      "store_id": 1
    },
    {
      "id": 83695,
      "store_id": 51
    },
    {
      "id": 83696,
      "store_id": 76
    },
    {
      "id": 104792,
      "store_id": 101,
      "role": 1
    }
  ],
  "leader": {
    "id": 83694,
    "store_id": 1
  },
  "written_bytes": 3300070,
  "read_bytes": 787118,
  "written_keys": 15994,
  "read_keys": 3226,
  "approximate_size": 56,
  "approximate_keys": 263273
}

SELECT * FROM INFORMATION_SCHEMA.TIKV_REGION_PEERS WHERE REGION_ID=83693;
+-----------+---------+----------+------------+-----------+--------+--------------+
| REGION_ID | PEER_ID | STORE_ID | IS_LEARNER | IS_LEADER | STATUS | DOWN_SECONDS |
+-----------+---------+----------+------------+-----------+--------+--------------+
|     83693 |   83694 |        1 |          0 |         1 | NORMAL |         NULL |
|     83693 |   83695 |       51 |          0 |         0 | NORMAL |         NULL |
|     83693 |   83696 |       76 |          0 |         0 | NORMAL |         NULL |
|     83693 |  104792 |      101 |          0 |         0 | NORMAL |         NULL |
+-----------+---------+----------+------------+-----------+--------+--------------+

4. What is your TiDB version? (Required)

Release Version: v5.0.0
Edition: Community
Git Commit Hash: bdac0885cd11bdf571aad9353bfc24e13554b91c
Git Branch: heads/refs/tags/v5.0.0
UTC Build Time: 2021-04-06 16:36:29
GoVersion: go1.13
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false

5. Related ISSUE and PR

kvproto#658
pd#3372

[ti-srebot]

Please edit this comment or add a new comment to complete the following information

Not a bug

1. Remove the 'type/bug' label
2. Add notes to indicate why it is not a bug

Duplicate bug

1. Add the 'type/duplicate' label
2. Add the link to the original bug

Bug

Note: Make Sure that 'component', and 'severity' labels are added
Example for how to fill out the template: #20100

1. Root Cause Analysis (RCA) (optional)

2. Symptom (optional)

3. All Trigger Conditions (optional)

4. Workaround (optional)

5. Affected versions

6. Fixed versions