6

I recently broke replication and when I tried to get past the one incorrect transaction. I got the following.

MariaDB [(none)]> STOP SLAVE;
Query OK, 0 rows affected (0.05 sec)

MariaDB [(none)]> SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1;
ERROR 1966 (HY000): When using parallel replication and GTID with multiple replication domains, @@sql_slave_skip_counter cannot be used. Instead, setting @@gtid_slave_pos explicitly can be used to skip to after a given GTID position.
MariaDB [(none)]> select @@gtid_slave_pos;
+---------------------------------------------+
| @@gtid_slave_pos                            |
+---------------------------------------------+
| 0-1051-1391406,1-1050-1182069,57-1051-98897 |
+---------------------------------------------+
1 row in set (0.00 sec)

MariaDB [(none)]> show variables like '%_pos%';
+----------------------+---------------------------------------------------------+
| Variable_name        | Value                                                   |
+----------------------+---------------------------------------------------------+
| gtid_binlog_pos      | 0-1051-1391406,2-1051-4474,57-1051-98897                |
| gtid_current_pos     | 0-1051-1391406,1-1050-1182069,2-1051-4474,57-1051-98897 |
| gtid_slave_pos       | 0-1051-1391406,1-1050-1182069,57-1051-98897             |
| wsrep_start_position | 00000000-0000-0000-0000-000000000000:-1                 |
+----------------------+---------------------------------------------------------+

What do I need to do to fix this.

Update 1

MariaDB [(none)]> show variables like '%gtid%';
+------------------------+------------------------------------------+
| Variable_name          | Value                                    |
+------------------------+------------------------------------------+
| gtid_binlog_pos        | 1-1050-4820789,2-1051-379101,3-1010-3273 |
| gtid_binlog_state      | 1-1050-4820789,2-1051-379101,3-1010-3273 |
| gtid_current_pos       | 1-1050-4819948,2-1051-379101,3-1010-3273 |
| gtid_domain_id         | 3                                        |
| gtid_ignore_duplicates | OFF                                      |
| gtid_seq_no            | 0                                        |
| gtid_slave_pos         | 1-1050-4819948,2-1051-379101,3-1010-3273 |
| gtid_strict_mode       | OFF                                      |
| last_gtid              |                                          |
| wsrep_gtid_domain_id   | 0                                        |
| wsrep_gtid_mode        | OFF                                      |
+------------------------+------------------------------------------+

I tried the following as per the instructions to set the @@gtid_slave_pos;

MariaDB [(none)]> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: [redacted]
                  Master_User: [redacted]
                  Master_Port: 3306
                Connect_Retry: 5
              Master_Log_File: binary.000591
          Read_Master_Log_Pos: 526511543
               Relay_Log_File: tmsdb-relay-bin.001239
                Relay_Log_Pos: 4
        Relay_Master_Log_File: binary.000591
             Slave_IO_Running: Yes
            Slave_SQL_Running: No
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 1062
                   Last_Error: Could not execute Write_rows_v1 event on table [redacted] Duplicate entry '1134890' for key 'PRIMARY', Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the event's master log binary.000591, end_log_pos 60726493
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 60724897
              Relay_Log_Space: 465787660
              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: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 1062
               Last_SQL_Error: Could not execute Write_rows_v1 event on table [redacted] Duplicate entry '1134890' for key 'PRIMARY', Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the event's master log binary.000591, end_log_pos 60726493
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1050
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
                   Using_Gtid: Current_Pos
                  Gtid_IO_Pos: 1-1050-4827753,2-1051-379101,3-1010-3273
      Replicate_Do_Domain_Ids: 
  Replicate_Ignore_Domain_Ids: 
                Parallel_Mode: optimistic
1 row in set (0.00 sec)

Using the gtid_slave_pos varialbe

MariaDB [(none)]> select @@gtid_slave_pos\G;
*************************** 1. row ***************************
@@gtid_slave_pos: 1-1050-4819948,2-1051-379101,3-1010-3273

MariaDB [(none)]> stop slave;
Query OK, 0 rows affected (0.21 sec)

MariaDB [(none)]> SET GLOBAL gtid_slave_pos='1-1050-4819948,2-1051-379101,3-1010-3274';
Query OK, 0 rows affected (0.10 sec)

MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.21 sec)

When I check the status after running the above Got fatal error 1236 from master when reading data from binary log: 'Error: connecting slave requested to start from GTID 3-1010-3274, which is not in the master's binlog'

MariaDB [(none)]> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: 
                  Master_Host: 10.56.228.64
                  Master_User: maxscale
                  Master_Port: 3306
                Connect_Retry: 5
              Master_Log_File: binary.000591
          Read_Master_Log_Pos: 60724897
               Relay_Log_File: tmsdb-relay-bin.001239
                Relay_Log_Pos: 4
        Relay_Master_Log_File: binary.000591
             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: 60724897
              Relay_Log_Space: 249
              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: NULL
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: 'Error: connecting slave requested to start from GTID 3-1010-3274, which is not in the master's binlog'
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1050
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
                   Using_Gtid: Current_Pos
                  Gtid_IO_Pos: 1-1050-4819948,2-1051-379101,3-1010-3274
      Replicate_Do_Domain_Ids: 
  Replicate_Ignore_Domain_Ids: 
                Parallel_Mode: optimistic
1 row in set (0.00 sec)

I can get this back to the previous state by

MariaDB [(none)]> stop slave;
Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> SET GLOBAL gtid_slave_pos='1-1050-4819948,2-1051-379101,3-1010-3273';
Query OK, 0 rows affected (0.09 sec)

MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.06 sec)
0

2 Answers 2

4

I found the following worked for me. This does not restore a slave into state that is an exact replica of master. There will be data differences. I will use pt-table-sync to fix those.

1. Restart Replication without GTID method
2. Stop Parallel slave threads
3. Enable GTID replication
4. Using percona-toolkit pt-slave-restart to skip past all the errors.

1. Restart Replication without GTID method Using master binglog position

CHANGE MASTER TO MASTER_HOST='12.34.56.789',MASTER_USER='slave_user', MASTER_PASSWORD='password', MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=  107;

This is well documented, Please google and find instructions.

2. Stop Parallel slave threads

This was part of the problem as seen in the original question.

ERROR 1966 (HY000): When using parallel replication and GTID with multiple replication domains, @@sql_slave_skip_counter cannot be used. Instead, setting @@gtid_slave_pos explicitly can be used to skip to after a given GTID position.

I want to be able to skip events and not worry about trying to figure out or increase the GTID position for everyone.

MariaDB [(none)]> stop slave;
Query OK, 0 rows affected (0.35 sec)
MariaDB [(none)]> set global slave_parallel_threads = 0;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> set global slave_parallel_mode = none;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> Start SLAVE;
Query OK, 0 rows affected (0.00 sec)    

Now if I check Parallel slave threads I see

MariaDB [(none)]> show slave status \G
*************************** 1. row ***************************
     ..........
                Parallel_Mode: none

I can reverse this process to re-enable Parallel slave threads when I am done. And I know that GTID is working.

3. Enable GTID replication

I can now try restarting the slave with GTID enabled.

On the master

MariaDB [(none)]> SHOW MASTER STATUS\G
*************************** 1. row ***************************
            File: mariadb-bin.000001
        Position: 510
    Binlog_Do_DB:
Binlog_Ignore_DB:
1 row in set (0.00 sec)

SELECT BINLOG_GTID_POS('mariadb-bin.000001', 510);
+--------------------------------------------+
| BINLOG_GTID_POS('mariadb-bin.000001', 510) |
+--------------------------------------------+
| 1-101-1                                    |
+--------------------------------------------+
1 row in set (0.00 sec)

On the slave

STOP SLAVE;
SET GLOBAL gtid_slave_pos = '1-101-1';
CHANGE MASTER TO master_use_gtid=slave_pos;
START SLAVE;

Now when I check the slave it has some events to skip to get back into the same state as the master.

Last_Error: An attempt was made to binlog GTID 1-1050-5004291 which would create an out-of-order sequence number with existing GTID 1-1050-5004322, and gtid strict mode is enabled.

MariaDB [(none)]> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
              Master_Log_File: binary.000599
          Read_Master_Log_Pos: 364810491
               Relay_Log_File: tmsdb-relay-bin.001240
                Relay_Log_Pos: 716
        Relay_Master_Log_File: binary.000599
             Slave_IO_Running: Yes
            Slave_SQL_Running: No
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 1950
                   Last_Error: An attempt was made to binlog GTID 1-1050-5004291 which would create an out-of-order sequence number with existing GTID 1-1050-5004322, and gtid strict mode is enabled.
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 286447058
              Relay_Log_Space: 78364447
              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: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 1950
               Last_SQL_Error: An attempt was made to binlog GTID 1-1050-5004291 which would create an out-of-order sequence number with existing GTID 1-1050-5004322, and gtid strict mode is enabled.
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1050
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
                   Using_Gtid: Slave_Pos
                  Gtid_IO_Pos: 1-1050-5005223,2-1051-379101,3-1010-3273
      Replicate_Do_Domain_Ids: 
  Replicate_Ignore_Domain_Ids: 
                Parallel_Mode: none
1 row in set (0.00 sec)

4. Using percona-toolkit pt-slave-restart to skip past all the errors

sudo yum install http://www.percona.com/downloads/percona-release/redhat/0.1-4/percona-release-0.1-4.noarch.rpm
sudo yum search percona-toolkit

pt-slave-restart will skip all the events need to get the slave into a working state.

# pt-slave-restart 
2017-12-22T13:39:59  tmsdb-relay-bin.001240         716 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240       69702 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240       97912 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240       98144 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      363903 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      364135 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      712776 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      713008 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      759737 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      827932 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      828164 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      934851 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      952088 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240      952320 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1084249 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1084481 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1351188 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1351420 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1621561 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1693920 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1711677 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1711909 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1880931 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1881163 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     1916544 1950 
2017-12-22T13:40:00  tmsdb-relay-bin.001240     2124672 1950 
2017-12-22T13:40:01  tmsdb-relay-bin.001240     2124904 1950 
2017-12-22T13:40:01  tmsdb-relay-bin.001240     2125136 1950 
2017-12-22T13:40:01  tmsdb-relay-bin.001240     2452030 1950 
2017-12-22T13:40:01  tmsdb-relay-bin.001240     2452262 1950 
2017-12-22T13:40:01  tmsdb-relay-bin.001240     2819749 1950 
2017-12-22T13:40:01  tmsdb-relay-bin.001240     2819981 1950 

Now when I check my slave status

MariaDB [(none)]> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: masterhost
                  Master_User: maxscale
                  Master_Port: 3306
                Connect_Retry: 5
              Master_Log_File: binary.000600
          Read_Master_Log_Pos: 37801368
               Relay_Log_File: tmsdb-relay-bin.001242
                Relay_Log_Pos: 37801653
        Relay_Master_Log_File: binary.000600
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 37801368
              Relay_Log_Space: 37801991
              Until_Condition: None
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
             Master_Server_Id: 1050
                   Using_Gtid: Slave_Pos
                  Gtid_IO_Pos: 1-1050-5014401,2-1051-379101,3-1010-3273
                Parallel_Mode: none
1 row in set (0.00 sec)

Lastly I need to restart the server and make sure it is reboot safe, etc.

2
1

I have found in production that Parallel_Mode is the most likely cause of my problems.

I recommend using a different value from optimistic

MariaDB [(none)]> select @@slave_parallel_mode\G
*************************** 1. row ***************************
@@slave_parallel_mode: optimistic

If you get the following errors.

pt-slave-restart 
2018-02-09T10:39:19  tmsdb-relay-bin.000388           4 1032 
DBD::mysql::st execute failed: When using parallel replication and GTID with multiple replication domains, @@sql_slave_skip_counter can not be used. Instead, setting @@gtid_slave_pos explicitly can be used to skip to after a given GTID position. [for Statement "SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1"] at /bin/pt-slave-restart line 5122.

In the logs I see the following:

tail /var/log/mariadb.log
2018-02-09 10:35:46 139919003784960 [ERROR] Slave SQL: Could not execute Update_rows_v1 event on table [tablename]; Can't find record in '[tablename]', Error_code: 1032; handler error HA_ERR_KEY_NOT_FOUND; the event's master log binary.000953, end_log_pos 264325215, Gtid 1-1050-13462991, Internal MariaDB error code: 1032
2018-02-09 10:35:46 139919003784960 [Warning] Slave: Can't find record in '[tablename]' Error_code: 1032
2018-02-09 10:35:46 139919003784960 [ERROR] Error running query, slave SQL thread aborted. Fix the problem, and restart the slave SQL thread with "SLAVE START". We stopped at log 'binary.000953' position 262879171; GTID position '1-1050-13462990,2-1051-379101,3-1010-3273'
2018-02-09 10:35:46 139918776985344 [Note] Slave SQL thread exiting, replication stopped in log 'binary.000953' at position 262879171; GTID position '1-1050-13462990,2-1051-379101,3-1010-3273'

To restart the slave after it fails you can do the following.
Stop all slave_parallel_threads and disable slave_parallel_mode

MariaDB [(none)]> stop slave;
Query OK, 0 rows affected (0.35 sec)
MariaDB [(none)]> set global slave_parallel_threads = 0;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> set global slave_parallel_mode = none;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> Start SLAVE;
Query OK, 0 rows affected (0.00 sec)    

I now use pt-slave-restart to restart slaves as I don't have to think about sequence number and a whole bundle of other things that take too long when I just want to get the slave started.

pt-slave-restart

Will run without errors, you can ctrl-c to close it when you are happy that your slave has caught up.

This is not much different then, but it does it auto magically.

STOP SLAVE;  
SET GLOBAL sql_slave_skip_counter = 1;  
START SLAVE;  

If you need to have parallel threads then you can re-enable them once the slave has caught up or gotten past the event causing problems. I would try a different slave_parallel_mod like conservative

MariaDB [(none)]> stop slave;
Query OK, 0 rows affected (0.01 sec)
MariaDB [(none)]> set global slave_parallel_threads = 4;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> set global slave_parallel_mode = conservative;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.09 sec)

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