[MDEV-9974] STOP SLAVE behavior with no connection_name doesn't match documentation Created: 2016-04-22  Updated: 2016-04-28  Resolved: 2016-04-28

Status: Closed
Project: MariaDB Server
Component/s: Documentation
Affects Version/s: N/A
Fix Version/s: N/A

Type: Bug Priority: Major
Reporter: Geoff Montee (Inactive) Assignee: Ian Gilfillan
Resolution: Fixed Votes: 0
Labels: replication


 Description   

The documentation about STOP SLAVE says the following:

If there is only one master, or the default master (as specified by the default_master_connection system variable) is intended, connection_name can be omitted. If provided, the STOP SLAVE statement will apply to the specified master. connection_name is case-insensitive.

https://mariadb.com/kb/en/mariadb/stop-slave/

Let's say that I have the following slave configured:

MariaDB [(none)]> show all slaves status\G
 
*************************** 1. row ***************************
 
              Connection_name: 172-31-19-192
 
              Slave_SQL_State: Slave has read all relay log; waiting for the slave I/O thread to update it
 
               Slave_IO_State: Waiting for master to send event
 
                  Master_Host: 172.31.19.192
 
                  Master_User: repl
 
                  Master_Port: 3306
 
                Connect_Retry: 60
 
              Master_Log_File: mariadb-bin.000002
 
          Read_Master_Log_Pos: 3085
 
               Relay_Log_File: ip-172-31-22-174-relay-bin-172@002d31@002d19@002d192.000002
 
                Relay_Log_Pos: 2530
 
        Relay_Master_Log_File: mariadb-bin.000002
 
             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: 3085
 
              Relay_Log_Space: 2865
 
              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_SSL_Crl:
 
           Master_SSL_Crlpath:
 
                   Using_Gtid: Slave_Pos
 
                  Gtid_IO_Pos: 1-1-10,2-2-6
 
      Replicate_Do_Domain_Ids:
 
  Replicate_Ignore_Domain_Ids:
 
                Parallel_Mode: conservative
 
         Retried_transactions: 0
 
           Max_relay_log_size: 1073741824
 
         Executed_log_entries: 52
 
    Slave_received_heartbeats: 0
 
       Slave_heartbeat_period: 1800.000
 
               Gtid_Slave_Pos: 1-1-10,2-2-6
 
1 row in set (0.00 sec)

According to the documentation, I should be able to stop this slave by simply executing STOP SLAVE with no connection_name since there is only one master configured. However, this does not work:

MariaDB [(none)]> STOP SLAVE;
 
Query OK, 0 rows affected, 1 warning (0.00 sec)
 
 
 
MariaDB [(none)]> SHOW WARNINGS;
 
+-------+------+--------------------------------+
 
| Level | Code | Message                        |
 
+-------+------+--------------------------------+
 
| Note  | 1255 | Slave already has been stopped |
 
+-------+------+--------------------------------+
 
1 row in set (0.00 sec)
 
 
 
MariaDB [(none)]> show all slaves status\G
 
*************************** 1. row ***************************
 
              Connection_name: 172-31-19-192
 
              Slave_SQL_State: Slave has read all relay log; waiting for the slave I/O thread to update it
 
               Slave_IO_State: Waiting for master to send event
 
                  Master_Host: 172.31.19.192
 
                  Master_User: repl
 
                  Master_Port: 3306
 
                Connect_Retry: 60
 
              Master_Log_File: mariadb-bin.000002
 
          Read_Master_Log_Pos: 3085
 
               Relay_Log_File: ip-172-31-22-174-relay-bin-172@002d31@002d19@002d192.000002
 
                Relay_Log_Pos: 2530
 
        Relay_Master_Log_File: mariadb-bin.000002
 
             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: 3085
 
              Relay_Log_Space: 2865
 
              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_SSL_Crl:
 
           Master_SSL_Crlpath:
 
                   Using_Gtid: Slave_Pos
 
                  Gtid_IO_Pos: 1-1-10,2-2-6
 
      Replicate_Do_Domain_Ids:
 
  Replicate_Ignore_Domain_Ids:
 
                Parallel_Mode: conservative
 
         Retried_transactions: 0
 
           Max_relay_log_size: 1073741824
 
         Executed_log_entries: 52
 
    Slave_received_heartbeats: 0
 
       Slave_heartbeat_period: 1800.000
 
               Gtid_Slave_Pos: 1-1-10,2-2-6
 
1 row in set (0.00 sec)

Is the documentation incorrect, or is there a problem with the implementation?

 Comments   
Comment by Elena Stepanova [ 2016-04-22 ]

The documentation is inaccurate. It apparently assumes that if there is only one master, it will always be the old-fashioned nameless master, which of course is not necessarily the case.
It is so not only for STOP SLAVE, but for any other slave-related command which can have an optional master connection name – START SLAVE, RESET SLAVE, etc.

Comment by Ian Gilfillan [ 2016-04-28 ]

I clarified by specifying that it only works if there's one NAMELESS master, and added this to START SLAVE, STOP SLAVE, RESET SLAVE, CHANGE MASTER TO and SHOW RELAYLOG. I tested quite a few combinations, but not everything, but I think it should be correct as it stands. Let me know if I've missed anything.

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