Binary log events larger than max_allowed_packet can lead to slave failure even after fix of MySQL bug #60926

[Sveta Smirnova]

To fix bug #60926 new variable, --slave-max-allowed-packet, were introduced, but its size is limited to 1G. In this way if master created row event, larger than 1G, slave will fail.

How to repeat:
Start master and slave with max-allowed-packet=1G and slave-max-allowed-packet=1G (maximum)

On master:

set binlog_format='row';
create table t1(f1 longtext);
insert into t1 values(repeat('a', 1073741824/4));
create table t2 like t1;
flush logs;
insert into t2 select concat(f1,f1,f1,f1) from t1;

Ensure data inserted properly into t2:

mysql> select count(*) from t2;
+----------+
| count(*) |
+----------+
| 1 |
+----------+
1 row in set (0.00 sec)

On slave:

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State:
                  Master_Host: 127.0.0.1
                  Master_User: root
                  Master_Port: 13000
                Connect_Retry: 1
              Master_Log_File: master-bin.000002
          Read_Master_Log_Pos: 337
               Relay_Log_File: slave-relay-bin.000004
                Relay_Log_Pos: 369
        Relay_Master_Log_File: master-bin.000002
             Slave_IO_Running: No
            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: 154
              Relay_Log_Space: 807
              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: 1236
                Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'log event entry exceeded max_allowed_packet; Increase max_allowed_packet on master; the first event '' at 4, the last event read from './master-bin.000002' at 337, the last byte read from './master-bin.000002' at 356.'
               Last_SQL_Errno: 0
               Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
             Master_Server_Id: 1
                  Master_UUID: 4e4741d5-316d-11e5-9104-1caff70598d3
             Master_Info_File: /home/sveta/build/mysql-5.7/mysql-test/var/mysqld.2/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: 10
                  Master_Bind:
      Last_IO_Error_Timestamp: 150723 22:11:35
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set:
            Executed_Gtid_Set:
                Auto_Position: 0
         Replicate_Rewrite_DB:
                 Channel_Name:
1 row in set (0.01 sec)

mysql> select count(*) from t2;
+----------+
| count(*) |
+----------+
| 0 |
+----------+
1 row in set (0.00 sec)

Events less than 1G replicated successfully:

mysql> select count(*) from t1;
+----------+
| count(*) |
+----------+
| 1 |
+----------+
1 row in set (0.00 sec)

Suggested fix:
Make slave ignore max-allowed-packet value completely, because with ROW format is easy to create such big events

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-915