主库binlog被purge的情形

1.演示实验环境
--主库版本：
root@(none)>show variables like 'version';
+---------------+---------------------+
| Variable_name | Value               |
+---------------+---------------------+
| version       | 5.7.23-23-31.31-log |
+---------------+---------------------+
1 row in set (0.01 sec)

--复制模式
root@(none)>show variables like '%gtid_mode%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| gtid_mode     | ON    |
+---------------+-------+
1 row in set (0.00 sec)

--复制进程
root@(none)>show processlist;
+----+-----------------+---------------------+-------+------------------+-------+---------------------------------------------------------------+------------------+-----------+---------------+
| Id | User            | Host                | db    | Command          | Time  | State                                                         | Info             | Rows_sent | Rows_examined |
+----+-----------------+---------------------+-------+------------------+-------+---------------------------------------------------------------+------------------+-----------+---------------+
|  1 | event_scheduler | localhost           | NULL  | Daemon           | 14232 | Waiting on empty queue                                        | NULL             |         0 |             0 |
|  9 | repl            | 192.168.2.101:53422 | NULL  | Binlog Dump GTID | 11941 | Master has sent all binlog to slave; waiting for more updates | NULL             |         0 |             0 |
| 14 | root            | localhost           | NULL  | Query            |     0 | starting                                                      | show processlist |         0 |             0 |
+----+-----------------+---------------------+-------+------------------+-------+---------------------------------------------------------------+------------------+-----------+---------------+
8 rows in set (0.00 sec)

root@(none)>

--从库状态
root@(none)>show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.2.100
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000014
          Read_Master_Log_Pos: 194
               Relay_Log_File: relay-bin.000005
                Relay_Log_Pos: 407
        Relay_Master_Log_File: mysql-bin.000014
             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: 194
              Relay_Log_Space: 695
              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: 015d4d11-0363-11e9-bb6c-0800279a3030
             Master_Info_File: /mysql/3306/data/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: 015d4d11-0363-11e9-bb6c-0800279a3030:1-4
            Executed_Gtid_Set: 015d4d11-0363-11e9-bb6c-0800279a3030:1-4
                Auto_Position: 1
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)
root@(none)>

2.主库binlog被purge的情形
--停止从库，模拟从库宕机状态
root@pxc01>stop slave;
Query OK, 0 rows affected (0.02 sec)

root@pxc01>show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State:
                  Master_Host: 192.168.2.100
                  Master_User: repl
                  Master_Port: 3306
............
             Slave_IO_Running: No
            Slave_SQL_Running: No

--此时主库上的gtid_purged为空
root@(none)>show variables like '%gtid_purged%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| gtid_purged   |       |
+---------------+-------+
1 row in set (0.01 sec)

root@(none)>

--查看主库binlog
root@pxc01>show binary logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000009 |       154 |
| mysql-bin.000010 |       635 |
| mysql-bin.000011 |       201 |
| mysql-bin.000012 |       177 |
| mysql-bin.000013 |      1087 |
| mysql-bin.000014 |       706 |
+------------------+-----------+

--查看测试数据
root@pxc01>select * from tbx;
+------+
| id   |
+------+
|    1 |
|    2 |
|    3 |
+------+
3 rows in set (0.00 sec)

root@pxc01>

--从主库删除记录
root@pxc01>delete from tbx;
Query OK, 3 rows affected (0.09 sec)

root@pxc01>

--切换日志
root@pxc01>flush logs;
Query OK, 0 rows affected (0.08 sec)

root@pxc01>

--新增记录
root@pxc01>insert into tbx values(4);
root@pxc01>insert into tbx values(5);
root@pxc01>insert into tbx values(6);

--查看主库binlog
root@pxc01>show binary logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000009 |       154 |
| mysql-bin.000010 |       635 |
| mysql-bin.000011 |       201 |
| mysql-bin.000012 |       177 |
| mysql-bin.000013 |      1087 |
| mysql-bin.000014 |      1019 |
| mysql-bin.000015 |       962 |
+------------------+-----------+

--清理binlog
root@pxc01>purge binary logs to 'mysql-bin.000015';
Query OK, 0 rows affected (0.08 sec)

root@pxc01>show binary logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000015 |       962 |
+------------------+-----------+
1 row in set (0.00 sec)

root@pxc01>

--此时可以看到相应的gtid_purged值
root@pxc01>show variables like '%gtid_purged%';
+---------------+------------------------------------------+
| Variable_name | Value                                    |
+---------------+------------------------------------------+
| gtid_purged   | 015d4d11-0363-11e9-bb6c-0800279a3030:1-7 |
+---------------+------------------------------------------+
1 row in set (0.01 sec)

root@pxc01>

--下面启动从库
root@(none)>start slave;
Query OK, 0 rows affected (0.06 sec)

root@(none)>show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: 

             Slave_IO_Running: No
            Slave_SQL_Running: Yes
                Last_IO_Errno: 1236
                Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'The slave is connecting using CHANGE MASTER TO MASTER_AUTO_POSITION = 1, but the master has purged binary logs containing GTIDs that the slave requires.'
           Retrieved_Gtid_Set: 015d4d11-0363-11e9-bb6c-0800279a3030:1-6
            Executed_Gtid_Set: 015d4d11-0363-11e9-bb6c-0800279a3030:1-6
                Auto_Position: 1

-- 从库上gtid_purged参数，此时为空
root@(none)>show variables like '%gtid_purged%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| gtid_purged   |       |
+---------------+-------+
1 row in set (0.01 sec)

root@(none)>

--停止从库
root@(none)>stop slave;

--下面尝试使用gtid_purged进行跳过事务。
root@(none)>set global gtid_purged = '015d4d11-0363-11e9-bb6c-0800279a3030:1-7';
ERROR 1840 (HY000): @@GLOBAL.GTID_PURGED can only be set when @@GLOBAL.GTID_EXECUTED is empty.
root@(none)>
提示:仅仅当GLOBAL.GTID_EXECUTED为空才能被设置

--查看从库当前的gtid_executed。gtid_executed肯定是不为空，且这些gtid记录在从库的binary log中
root@(none)>show global variables like '%gtid_executed%'\G
*************************** 1. row ***************************
Variable_name: gtid_executed
        Value: 015d4d11-0363-11e9-bb6c-0800279a3030:1-6
*************************** 2. row ***************************
Variable_name: gtid_executed_compression_period
        Value: 1000
2 rows in set (0.01 sec)

root@(none)>

--下面我们在从库上reset master，即清空从库binlog
root@(none)>reset master;
Query OK, 0 rows affected (0.10 sec)

--再次查看gtid_executed已经为空值
root@(none)>show global variables like '%gtid_executed%'\G
*************************** 1. row ***************************
Variable_name: gtid_executed
        Value:
*************************** 2. row ***************************
Variable_name: gtid_executed_compression_period
        Value: 1000
2 rows in set (0.01 sec)

root@(none)>

--此时再次设置gtid_purged的值
root@(none)>set global gtid_purged = '015d4d11-0363-11e9-bb6c-0800279a3030:1-7';
Query OK, 0 rows affected (0.06 sec)

--启动从库
root@(none)>start slave;
root@(none)>show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.2.100
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000015
          Read_Master_Log_Pos: 962
               Relay_Log_File: relay-bin.000006
                Relay_Log_Pos: 1175
        Relay_Master_Log_File: mysql-bin.000015
             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: 962
              Relay_Log_Space: 2141
              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: 015d4d11-0363-11e9-bb6c-0800279a3030
             Master_Info_File: /mysql/3306/data/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: 015d4d11-0363-11e9-bb6c-0800279a3030:1-6:8-10
            Executed_Gtid_Set: 015d4d11-0363-11e9-bb6c-0800279a3030:1-10
                Auto_Position: 1
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)

注当前主从记录是不一致的：前期在主库delete的事务未传到从库，需要手动删除！
主库记录：
root@pxc01>select * from tbx;
+------+
| id   |
+------+
|    4 |
|    5 |
|    6 |
+------+
3 rows in set (0.00 sec)

root@pxc01>

从库记录:
root@pxc01>select * from tbx;
+------+
| id   |
+------+
|    1 |
|    2 |
|    3 |
|    4 |
|    5 |
|    6 |
+------+
6 rows in