Bug #77817 Bug #60926 was not fixed properly
Submitted: 23 Jul 2015 19:18 Modified: 24 Jul 2015 6:44
Reporter: Sveta Smirnova (OCA) Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: Row Based Replication ( RBR ) Severity:S3 (Non-critical)
Version:5.6.25, 5.7.7, 5.6.27, 5.7.9 OS:Any
Assigned to: CPU Architecture:Any

[23 Jul 2015 19:18] Sveta Smirnova
Description:
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 (I saw 18G event!).
[24 Jul 2015 6:44] Umesh Shastry
Hello Sveta,

Thank you for the report and test case.
Observed this with 5.6.25, 5.6.27 and 5.7.9 builds.

Thanks,
Umesh
[24 Jul 2015 6:44] Umesh Shastry
test results

Attachment: 77817.results (application/octet-stream, text), 52.65 KiB.