Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'Could not find  first log file name in binary log index file'

# 調査
## On Replica

```
mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: 
                  Master_Host: 10.146.0.18
                  Master_User: rpl_user
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000091
          Read_Master_Log_Pos: 1372
               Relay_Log_File: mysql-relay-bin.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File: mysql-bin.000091
```

## On Read

```
mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000039 |     1724 |              |                  |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
```

# 対応

ログファイルやポジションがリードとレプリカでずれてしまっているので修正する。

## On Replica

```
> stop slave;
Query OK, 0 rows affected (0.02 sec)

> CHANGE MASTER TO MASTER_HOST='10.146.0.18', MASTER_LOG_FILE='binlog.000039', MASTER_LOG_POS=1724;
Query OK, 0 rows affected (0.05 sec)

> start slave;
Query OK, 0 rows affected (0.00 sec)

> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.146.0.18
                  Master_User: rpl_user
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: binlog.000039
          Read_Master_Log_Pos: 1724
               Relay_Log_File: mysql-relay-bin.000002
                Relay_Log_Pos: 321
        Relay_Master_Log_File: binlog.000039
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 1724
              Relay_Log_Space: 530
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1
                  Master_UUID: bad88ce0-20c2-11eb-959f-42010a920012
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
       Master_public_key_path: 
        Get_master_public_key: 0
            Network_Namespace: 
1 row in set, 1 warning (0.00 sec)

```

## ON Read

リードからもSlaveが認識てきていることを確認。

```
mysql> show slave hosts;
+-----------+------+------+-----------+--------------------------------------+
| Server_id | Host | Port | Master_id | Slave_UUID                           |
+-----------+------+------+-----------+--------------------------------------+
|         2 |      | 3306 |         1 | 74XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX14 |
+-----------+------+------+-----------+--------------------------------------+
1 row in set, 1 warning (0.00 sec)
```



https://dba.stackexchange.com/questions/139131/error-1236-could-not-find-first-log-file-name-in-binary-log-index-file