如果将relay_log_recovery设置为0会发生什么?

在MySQL5.7版本中,开启并行复制后,设置relay-log-recovery=1,从库启动后偶尔会报错,如果将relay-log-recovery设置为0,会发生什么呢?

作者 韩杰·沃趣科技MySQL数据库工程师
出品 沃趣科技

| 背景

在MySQL5.7版本中,开启并行复制后,设置relay-log-recovery=1,从库启动后偶尔会报错,类似于https://bugs.mysql.com/bug.php?id=83713,所以尝试将relay-log-recovery设置为0,观察会发生什么。

| 环境

  • MySQL5.7.22
  • GTID模式
  • relay-log-recovery=0
  • relay_log_purge=off
  • sync_relay_log = 10000
  • relay_log_info_repository = TABLE
  • 不开启并行复制

| 模拟relay-log没有sync完全

Retrieved_Gtid_Set < Executed_Gtid_Set

停掉slave,查看相关信息

[root@shadow:/root 5.7.22-log_Instance1 root@localhost:(none) 17:20:34]>stop slave;
Query OK, 0 rows affected (0.01 sec)
[root@shadow:/root 5.7.22-log_Instance1 root@localhost:(none) 17:20:37]>select * from mysql.slave_relay_log_info;show slave status\G
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| Number_of_lines | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Sql_delay | Number_of_workers | Id | Channel_name |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| 7 | /home/mysql/data/mysqldata1/relaylog/mysql-relay-bin.000017 | 186094 | mysql-bin.000001 | 4941307 | 0 | 0 | 1 | |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
1 row in set (0.00 sec)
*************************** 1. row ***************************
               Slave_IO_State:
                  Master_Host: 10.10.30.18
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 10
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 4941307
               Relay_Log_File: mysql-relay-bin.000017
                Relay_Log_Pos: 186094
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: No
            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: 0
                   Last_Error:
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 4941307
              Relay_Log_Space: 4315819
              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: 0
               Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
             Master_Server_Id: 330618
                  Master_UUID: 2662c965-fdb2-11e8-8157-0cc47a3aae0d
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State:
           Master_Retry_Count: 86400
                  Master_Bind:
      Last_IO_Error_Timestamp:
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set: 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-101:104-1504:1509-2079:2082-11822
            Executed_Gtid_Set: 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-11822
                Auto_Position: 1
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)

关闭数据库stopmysql

$stopmysql

查看最后一个relaylog中的最后一个事务的GTID为2662c965-fdb2-11e8-8157-0cc47a3aae0d:11822

$mysqlbinlog -vvv mysql-relay-bin.000017
# at 185676
#181214 17:20:36 server id 330618 end_log_pos 4940954 CRC32 0xc2acb86d GTID last_committed=11821 sequence_number=11822 rbr_only=yes
/*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/;
SET @@SESSION.GTID_NEXT= '2662c965-fdb2-11e8-8157-0cc47a3aae0d:11822'/*!*/;
# at 185741
#181214 17:20:36 server id 330618 end_log_pos 4941046 CRC32 0x516997b4 Query thread_id=60654 exec_time=0 error_code=0
SET TIMESTAMP=1544779236/*!*/;
BEGIN
/*!*/;
# at 185833
#181214 17:20:36 server id 330618 end_log_pos 4941139 CRC32 0x65ea73eb Rows_query
# update qdata_mysql_heartbeat set ts=now() where server_id=@@server_id
# at 185926
#181214 17:20:36 server id 330618 end_log_pos 4941212 CRC32 0xb88fd1db Table_map: `qdata_mysql`.`qdata_mysql_heartbeat` mapped to number 108
# at 185999
#181214 17:20:36 server id 330618 end_log_pos 4941276 CRC32 0x67572f7a Update_rows: table id 108 flags: STMT_END_F
BINLOG '
5HUTXB16CwUAXQAAAFNlSwCAAEV1cGRhdGUgcWRhdGFfbXlzcWxfaGVhcnRiZWF0IHNldCB0cz1u
b3coKSB3aGVyZSBzZXJ2ZXJfaWQ9QEBzZXJ2ZXJfaWTrc+pl
5HUTXBN6CwUASQAAAJxlSwAAAGwAAAAAAAEAC3FkYXRhX215c3FsABVxZGF0YV9teXNxbF9oZWFy
dGJlYXQAAggSAQAA29GPuA==
5HUTXB96CwUAQAAAANxlSwAAAGwAAAAAAAEAAgAC///8egsFAAAAAACZoZ0VI/x6CwUAAAAAAJmh
nRUkei9XZw==
'/*!*/;
### UPDATE `qdata_mysql`.`qdata_mysql_heartbeat`
### WHERE
### @1=330618 /* LONGINT meta=0 nullable=0 is_null=0 */
### @2='2018-12-14 17:20:35' /* DATETIME(0) meta=0 nullable=0 is_null=0 */
### SET
### @1=330618 /* LONGINT meta=0 nullable=0 is_null=0 */
### @2='2018-12-14 17:20:36' /* DATETIME(0) meta=0 nullable=0 is_null=0 */
# at 186063
#181214 17:20:36 server id 330618 end_log_pos 4941307 CRC32 0x78f64c71 Xid = 776909
COMMIT/*!*/;
# at 186094
#181214 17:21:45 server id 330619 end_log_pos 186117 CRC32 0x014899bc Stop
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;
# End of log file
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;

用以下命令模拟relaylog丢失,这样mysql重新启动的时候初始化的Retrieved_Gtid_Set集合会比Executed_Gtid_Set集合小

$dd if=mysql-relay-bin.000017 of=/tmp/mysql-relay-bin.000017 bs=1 count=185090
$mv /tmp/mysql-relay-bin.000017 ./
$chown -R mysql:mysql *
##185090处对应的是2662c965-fdb2-11e8-8157-0cc47a3aae0d:11820这个事务,所以GTID为2662c965-fdb2-11e8-8157-0cc47a3aae0d:11820的事务被截断,2662c965-fdb2-11e8-8157-0cc47a3aae0d:11821、2662c965-fdb2-11e8-8157-0cc47a3aae0d:11822被抹掉
# at 184840
#181214 17:20:34 server id 330618 end_log_pos 4940118 CRC32 0xf6f3aed0 GTID last_committed=11819    sequence_number=11820   rbr_only=yes
/*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/;
SET @@SESSION.GTID_NEXT= '2662c965-fdb2-11e8-8157-0cc47a3aae0d:11820'/*!*/;
# at 184905
#181214 17:20:34 server id 330618 end_log_pos 4940210 CRC32 0x22409fbf Query thread_id=60652    exec_time=0 error_code=0
SET TIMESTAMP=1544779234/*!*/;
BEGIN
/*!*/;
# at 184997
#181214 17:20:34 server id 330618 end_log_pos 4940303 CRC32 0x436ed81d Rows_query
# update qdata_mysql_heartbeat set ts=now() where server_id=@@server_id
# at 185090
#181214 17:20:34 server id 330618 end_log_pos 4940376 CRC32 0xaadcb170 Table_map: `qdata_mysql`.`qdata_mysql_heartbeat` mapped to number 108
# at 185163
#181214 17:20:34 server id 330618 end_log_pos 4940440 CRC32 0xabc65d06 Update_rows: table id 108 flags: STMT_END_F

启动数据库startmysql

$startmysql

查看复制状态是否正常,复制正常。
且看到是从2662c965-fdb2-11e8-8157-0cc47a3aae0d:11823开始拉取binlog,因为UNION的GTID集合为2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-11822。

[root@shadow:/root 5.7.22-log_Instance1 root@localhost:(none) 17:35:33]>select * from mysql.slave_relay_log_info;show slave status\G
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| Number_of_lines | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Sql_delay | Number_of_workers | Id | Channel_name |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| 7 | /home/mysql/data/mysqldata1/relaylog/mysql-relay-bin.000019 | 371686 | mysql-bin.000001 | 5312491 | 0 | 0 | 1 | |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
1 row in set (0.00 sec)
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.10.30.18
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 10
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 5312491
               Relay_Log_File: mysql-relay-bin.000019
                Relay_Log_Pos: 371686
        Relay_Master_Log_File: mysql-bin.000001
             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: 5312491
              Relay_Log_Space: 4686796
              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: 330618
                  Master_UUID: 2662c965-fdb2-11e8-8157-0cc47a3aae0d
             Master_Info_File: mysql.slave_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: 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-101:104-1504:1509-2079:2082-11819:11823-12710
            Executed_Gtid_Set: 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-12710
                Auto_Position: 1
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)

查看error.log相关信息

2018-12-14T17:34:42.471162+08:00 1 [Note] Slave I/O thread for channel '': connected to master 'repl@10.10.30.18:3306',replication started in log 'mysql-bin.000001' at position 4941307
2018-12-14T17:34:42.474786+08:00 0 [Note] Event Scheduler: Loaded 0 events
2018-12-14T17:34:42.474921+08:00 0 [Note] /usr/local/mysql/bin/mysqld: ready for connections.
Version: '5.7.22-log' socket: '/home/mysql/data/mysqldata1/sock/mysql.sock' port: 3306 MySQL Community Server (GPL)
2018-12-14T17:34:42.476711+08:00 2 [Note] Slave SQL thread for channel '' initialized, starting replication in log 'mysql-bin.000001' at position 4941307, relay log '/home/mysql/data/mysqldata1/relaylog/mysql-relay-bin.000017' position: 186094
2018-12-14T17:34:43.965844+08:00 5 [Note] Start binlog_dump to master_thread_id(5) slave_server(330618), pos(, 4)

查看下个relaylog信息

$mysqlbinlog -vvv mysql-relay-bin.000018
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#181214 17:34:42 server id 330619 end_log_pos 123 CRC32 0x0996b423 Start: binlog v 4, server v 5.7.22-log created 181214 17:34:42
# This Format_description_event appears in a relay log and was generated by the slave thread.
# at 123
#181214 17:34:42 server id 330619 end_log_pos 242 CRC32 0x8885f92a Previous-GTIDs
# 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-101:104-1504:1509-2079:2082-11819
# at 242
#181214 17:34:42 server id 330619 end_log_pos 295 CRC32 0x1a4ec323 Rotate to mysql-relay-bin.000019 pos: 4
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;
# End of log file
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;

查看再下个relaylog信息,发现是从2662c965-fdb2-11e8-8157-0cc47a3aae0d:11823开始拉取日志

$mysqlbinlog -vvv mysql-relay-bin.000019
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#181214 17:34:42 server id 330619 end_log_pos 123 CRC32 0x0996b423 Start: binlog v 4, server v 5.7.22-log created 181214 17:34:42
# This Format_description_event appears in a relay log and was generated by the slave thread.
# at 123
#181214 17:34:42 server id 330619 end_log_pos 242 CRC32 0x8885f92a Previous-GTIDs
# 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-101:104-1504:1509-2079:2082-11819
# at 242
#700101 8:00:00 server id 330618 end_log_pos 0 CRC32 0x073c3e73 Rotate to mysql-bin.000001 pos: 4
# at 289
#181214 13:52:24 server id 330618 end_log_pos 123 CRC32 0x0180f777 Start: binlog v 4, server v 5.7.22-log created 181214 13:52:24
BINLOG '
GEUTXA96CwUAdwAAAHsAAAAAAAQANS43LjIyLWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAXwAEGggAAAAICAgCAAAACgoKKioAEjQA
AXf3gAE=
'/*!*/;
# at 408
#181214 17:34:42 server id 0 end_log_pos 455 CRC32 0x3dfb4b92 Rotate to mysql-bin.000001 pos: 154
# at 455
#181214 17:34:42 server id 0 end_log_pos 502 CRC32 0x1ff57b1c Rotate to mysql-bin.000001 pos: 4941307
# at 502
#181214 17:20:37 server id 330618 end_log_pos 4941372 CRC32 0xa2232924 GTID last_committed=11822 sequence_number=11823 rbr_only=yes
/*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/;
SET @@SESSION.GTID_NEXT= '2662c965-fdb2-11e8-8157-0cc47a3aae0d:11823'/*!*/;
# at 567
#181214 17:20:37 server id 330618 end_log_pos 4941464 CRC32 0xdecc7ed2 Query thread_id=60655 exec_time=0 error_code=0
SET TIMESTAMP=1544779237/*!*/;
SET @@session.pseudo_thread_id=60655/*!*/;
SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
SET @@session.sql_mode=1436549152/*!*/;
SET @@session.auto_increment_increment=2, @@session.auto_increment_offset=1/*!*/;
/*!\C utf8 *//*!*/;
SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=83/*!*/;
SET @@session.time_zone='+08:00'/*!*/;
SET @@session.lc_time_names=0/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
BEGIN
/*!*/;
# at 659
#181214 17:20:37 server id 330618 end_log_pos 4941557 CRC32 0x17e36176 Rows_query
# update qdata_mysql_heartbeat set ts=now() where server_id=@@server_id
# at 752

再次查看mysql-relay-bin.000017中的内容,最后记录如下,多了WARNING的信息

$mysqlbinlog -vvv mysql-relay-bin.000017
BEGIN
/*!*/;
# at 184997
#181214 17:20:34 server id 330618 end_log_pos 4940303 CRC32 0x436ed81d Rows_query
# update qdata_mysql_heartbeat set ts=now() where server_id=@@server_id
WARNING: The range of printed events ends with a row event or a table map event that does not have the STMT_END_F flag set. This might be because the last statement was not fully written to the log, or because you are using a --stop-position or --stop-datetime that refers to an event in the middle of a statement. The event(s) from the partial statement have not been written to output.
ROLLBACK /* added by mysqlbinlog */ /*!*/;
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;
# End of log file
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;

Retrieved_Gtid_Set > Executed_Gtid_Set

停掉slave的sql线程,模拟Retrieved_Gtid_Set > Executed_Gtid_Set,如下:

[root@shadow:/root 5.7.22-log_Instance1 root@localhost:(none) 16:08:48]>stop slave sql_thread;
Query OK, 0 rows affected (0.00 sec)
[root@shadow:/root 5.7.22-log_Instance1 root@localhost:(none) 16:08:57]>select * from mysql.slave_relay_log_info;show slave status\G
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| Number_of_lines | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Sql_delay | Number_of_workers | Id | Channel_name |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| 7 | /home/mysql/data/mysqldata1/relaylog/mysql-relay-bin.000011 | 1787845 | mysql-bin.000001 | 3158537 | 0 | 0 | 1 | |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
1 row in set (0.00 sec)
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.10.30.18
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 10
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 3171077
               Relay_Log_File: mysql-relay-bin.000011
                Relay_Log_Pos: 1787845
        Relay_Master_Log_File: mysql-bin.000001
             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: 0
                   Last_Error:
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 3158537
              Relay_Log_Space: 2542538
              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: 0
               Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
             Master_Server_Id: 330618
                  Master_UUID: 2662c965-fdb2-11e8-8157-0cc47a3aae0d
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State:
           Master_Retry_Count: 86400
                  Master_Bind:
      Last_IO_Error_Timestamp:
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set: 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-101:104-1504:1509-2079:2082-7587
            Executed_Gtid_Set: 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-7557
                Auto_Position: 1
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)

关闭数据库stopmysql

$stopmysql

查看mysql-relay-bin.000011最后一个事务GTID为2662c965-fdb2-11e8-8157-0cc47a3aae0d:7604

$mysqlbinlog -vvv mysql-relay-bin.000011
COMMIT/*!*/;
# at 1807073
#181214 16:09:40 server id 330618 end_log_pos 3177830 CRC32 0xe6febde8 GTID last_committed=7603 sequence_number=7604    rbr_only=yes
/*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/;
SET @@SESSION.GTID_NEXT= '2662c965-fdb2-11e8-8157-0cc47a3aae0d:7604'/*!*/;
# at 1807138
#181214 16:09:40 server id 330618 end_log_pos 3177922 CRC32 0x83a67d51 Query thread_id=56362    exec_time=0 error_code=0
SET TIMESTAMP=1544774980/*!*/;
BEGIN
/*!*/;
# at 1807230
#181214 16:09:40 server id 330618 end_log_pos 3178015 CRC32 0x904b0728 Rows_query
# update qdata_mysql_heartbeat set ts=now() where server_id=@@server_id
# at 1807323
#181214 16:09:40 server id 330618 end_log_pos 3178088 CRC32 0xd4354200 Table_map: `qdata_mysql`.`qdata_mysql_heartbeat` mapped to number 108
# at 1807396
#181214 16:09:40 server id 330618 end_log_pos 3178152 CRC32 0xc545f0a4 Update_rows: table id 108 flags: STMT_END_F
BINLOG '
RGUTXB16CwUAXQAAAB9+MACAAEV1cGRhdGUgcWRhdGFfbXlzcWxfaGVhcnRiZWF0IHNldCB0cz1u
b3coKSB3aGVyZSBzZXJ2ZXJfaWQ9QEBzZXJ2ZXJfaWQoB0uQ
RGUTXBN6CwUASQAAAGh+MAAAAGwAAAAAAAEAC3FkYXRhX215c3FsABVxZGF0YV9teXNxbF9oZWFy
dGJlYXQAAggSAQAAAEI11A==
RGUTXB96CwUAQAAAAKh+MAAAAGwAAAAAAAEAAgAC///8egsFAAAAAACZoZ0CZ/x6CwUAAAAAAJmh
nQJopPBFxQ==
'/*!*/;
### UPDATE `qdata_mysql`.`qdata_mysql_heartbeat`
### WHERE
### @1=330618 /* LONGINT meta=0 nullable=0 is_null=0 */
### @2='2018-12-14 16:09:39' /* DATETIME(0) meta=0 nullable=0 is_null=0 */
### SET
### @1=330618 /* LONGINT meta=0 nullable=0 is_null=0 */
### @2='2018-12-14 16:09:40' /* DATETIME(0) meta=0 nullable=0 is_null=0 */
# at 1807460
#181214 16:09:40 server id 330618 end_log_pos 3178183 CRC32 0x6a5edec2 Xid = 764012
COMMIT/*!*/;
# at 1807491
#181214 16:09:51 server id 330619 end_log_pos 1807514 CRC32 0xed4f17f3 Stop
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;
# End of log file
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;

执行以下命令将GTID为2662c965-fdb2-11e8-8157-0cc47a3aae0d:7600的事务截掉一半,2662c965-fdb2-11e8-8157-0cc47a3aae0d:7601、2662c965-fdb2-11e8-8157-0cc47a3aae0d:7602、2662c965-fdb2-11e8-8157-0cc47a3aae0d:7603、2662c965-fdb2-11e8-8157-0cc47a3aae0d:7604全部抹掉

$dd if=mysql-relay-bin.000011 of=/tmp/mysql-relay-bin.000011 bs=1 count=1805788
$mv /tmp/mysql-relay-bin.000011 ./
$chown -R mysql:mysql *
##1805788这个位点对应事务的GTID为2662c965-fdb2-11e8-8157-0cc47a3aae0d:7600
# at 1805401
#181214 16:09:36 server id 330618 end_log_pos 3176158 CRC32 0xeb1649f2 GTID last_committed=7599 sequence_number=7600 rbr_only=yes
/*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/;
SET @@SESSION.GTID_NEXT= '2662c965-fdb2-11e8-8157-0cc47a3aae0d:7600'/*!*/;
# at 1805466
#181214 16:09:36 server id 330618 end_log_pos 3176250 CRC32 0x9e2a31e5 Query thread_id=56358 exec_time=0 error_code=0
SET TIMESTAMP=1544774976/*!*/;
BEGIN
/*!*/;
# at 1805558
#181214 16:09:36 server id 330618 end_log_pos 3176343 CRC32 0x920329a0 Rows_query
# update qdata_mysql_heartbeat set ts=now() where server_id=@@server_id
# at 1805651
#181214 16:09:36 server id 330618 end_log_pos 3176416 CRC32 0x2204d593 Table_map: `qdata_mysql`.`qdata_mysql_heartbeat` mapped to number 108
# at 1805724
#181214 16:09:36 server id 330618 end_log_pos 3176480 CRC32 0x2f91a93a Update_rows: table id 108 flags: STMT_END_F
BINLOG '
QGUTXB16CwUAXQAAAJd3MACAAEV1cGRhdGUgcWRhdGFfbXlzcWxfaGVhcnRiZWF0IHNldCB0cz1u
b3coKSB3aGVyZSBzZXJ2ZXJfaWQ9QEBzZXJ2ZXJfaWSgKQOS
QGUTXBN6CwUASQAAAOB3MAAAAGwAAAAAAAEAC3FkYXRhX215c3FsABVxZGF0YV9teXNxbF9oZWFy
dGJlYXQAAggSAQAAk9UEIg==
QGUTXB96CwUAQAAAACB4MAAAAGwAAAAAAAEAAgAC///8egsFAAAAAACZoZ0CY/x6CwUAAAAAAJmh
nQJkOqmRLw==
'/*!*/;
### UPDATE `qdata_mysql`.`qdata_mysql_heartbeat`
### WHERE
### @1=330618 /* LONGINT meta=0 nullable=0 is_null=0 */
### @2='2018-12-14 16:09:35' /* DATETIME(0) meta=0 nullable=0 is_null=0 */
### SET
### @1=330618 /* LONGINT meta=0 nullable=0 is_null=0 */
### @2='2018-12-14 16:09:36' /* DATETIME(0) meta=0 nullable=0 is_null=0 */
# at 1805788
#181214 16:09:36 server id 330618 end_log_pos 3176511 CRC32 0xa6103d84 Xid = 764000
COMMIT/*!*/;

启动数据库startmysql

$startmysql

查看复制状态是否正常,显示正常。

[root@shadow:/root 5.7.22-log_Instance1 root@localhost:(none) 16:19:05]>select * from mysql.slave_relay_log_info;show slave status\G
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| Number_of_lines | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Sql_delay | Number_of_workers | Id | Channel_name |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| 7 | /home/mysql/data/mysqldata1/relaylog/mysql-relay-bin.000013 | 236672 | mysql-bin.000001 | 3412263 | 0 | 0 | 1 | |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
1 row in set (0.00 sec)
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.10.30.18
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 10
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 3412263
               Relay_Log_File: mysql-relay-bin.000013
                Relay_Log_Pos: 236672
        Relay_Master_Log_File: mysql-bin.000001
             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: 3412263
              Relay_Log_Space: 2784908
              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: 330618
                  Master_UUID: 2662c965-fdb2-11e8-8157-0cc47a3aae0d
             Master_Info_File: mysql.slave_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: 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-101:104-1504:1509-2079:2082-8164
            Executed_Gtid_Set: 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-8164
                Auto_Position: 1
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)

查看error.log

2018-12-14T16:17:37.822661+08:00 1 [Note] Slave SQL thread for channel '' initialized, starting replication in log 'mysql-bin.000001' at position 3158537, relay log '/home/mysql/data/mysqldata1/relaylog/mysql-relay-bin.000011' position: 1787845
2018-12-14T16:17:37.822915+08:00 2 [Note] Slave I/O thread for channel '': connected to master 'repl@10.10.30.18:3306',replication started in log 'mysql-bin.000001' at position 2764613
2018-12-14T16:17:37.826982+08:00 0 [Note] Event Scheduler: Loaded 0 events
2018-12-14T16:17:37.827132+08:00 0 [Note] /usr/local/mysql/bin/mysqld: ready for connections.
Version: '5.7.22-log' socket: '/home/mysql/data/mysqldata1/sock/mysql.sock' port: 3306 MySQL Community Server (GPL)
2018-12-14T16:17:38.020740+08:00 1 [Note] Slave SQL for channel '': Rolling back unfinished transaction (no COMMIT or ROLLBACK in relay log). A probable cause is partial transaction left on relay log because of restarting IO thread with auto-positioning protocol. Error_code: 0
2018-12-14T16:17:39.639144+08:00 4 [Note] Start binlog_dump to master_thread_id(4) slave_server(330618), pos(, 4)

查看下一个relaylog的信息

$mysqlbinlog -vvv mysql-relay-bin.000012
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#181214 16:17:37 server id 330619 end_log_pos 123 CRC32 0x32f87201 Start: binlog v 4, server v 5.7.22-log created 181214 16:17:37
# This Format_description_event appears in a relay log and was generated by the slave thread.
# at 123
#181214 16:17:37 server id 330619 end_log_pos 242 CRC32 0x524f2179 Previous-GTIDs
# 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-101:104-1504:1509-2079:2082-7599
# at 242
#181214 16:17:37 server id 330619 end_log_pos 295 CRC32 0xfe1b4a1f Rotate to mysql-relay-bin.000013 pos: 4
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;
# End of log file
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;

查看再下一个relaylog的信息,发现确实会重新去拉取2662c965-fdb2-11e8-8157-0cc47a3aae0d:7600这个GTID对应的日志

$mysqlbinlog -vvv mysql-relay-bin.000013
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#181214 16:17:37 server id 330619 end_log_pos 123 CRC32 0x32f87201 Start: binlog v 4, server v 5.7.22-log created 181214 16:17:37
# This Format_description_event appears in a relay log and was generated by the slave thread.
# at 123
#181214 16:17:37 server id 330619 end_log_pos 242 CRC32 0x524f2179 Previous-GTIDs
# 2662c965-fdb2-11e8-8157-0cc47a3aae0d:1-101:104-1504:1509-2079:2082-7599
# at 242
#700101 8:00:00 server id 330618 end_log_pos 0 CRC32 0x073c3e73 Rotate to mysql-bin.000001 pos: 4
# at 289
#181214 13:52:24 server id 330618 end_log_pos 123 CRC32 0x0180f777 Start: binlog v 4, server v 5.7.22-log created 181214 13:52:24
BINLOG '
GEUTXA96CwUAdwAAAHsAAAAAAAQANS43LjIyLWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAXwAEGggAAAAICAgCAAAACgoKKioAEjQA
AXf3gAE=
'/*!*/;
# at 408
#181214 16:17:37 server id 0 end_log_pos 455 CRC32 0x340c6196 Rotate to mysql-bin.000001 pos: 154
# at 455
#181214 16:17:37 server id 0 end_log_pos 502 CRC32 0x62bfc8f3 Rotate to mysql-bin.000001 pos: 3176093
# at 502
#181214 16:09:36 server id 330618 end_log_pos 3176158 CRC32 0xeb1649f2 GTID last_committed=7599 sequence_number=7600 rbr_only=yes
/*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/;
SET @@SESSION.GTID_NEXT= '2662c965-fdb2-11e8-8157-0cc47a3aae0d:7600'/*!*/;
# at 567
#181214 16:09:36 server id 330618 end_log_pos 3176250 CRC32 0x9e2a31e5 Query thread_id=56358 exec_time=0 error_code=0
SET TIMESTAMP=1544774976/*!*/;
SET @@session.pseudo_thread_id=56358/*!*/;
SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
SET @@session.sql_mode=1436549152/*!*/;
SET @@session.auto_increment_increment=2, @@session.auto_increment_offset=1/*!*/;
/*!\C utf8 *//*!*/;
SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=83/*!*/;
SET @@session.time_zone='+08:00'/*!*/;
SET @@session.lc_time_names=0/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
BEGIN
/*!*/;
# at 659
#181214 16:09:36 server id 330618 end_log_pos 3176343 CRC32 0x920329a0 Rows_query
# update qdata_mysql_heartbeat set ts=now() where server_id=@@server_id
# at 752

| 总结

从error.log中能看到,MySQL重启后,Slave SQL thread会根据mysql.slave_relay_log_info表中记录的位置点信息去starting replication

[root@shadow:/root 5.7.22-log_Instance1 root@localhost:(none) 16:08:57]>select * from mysql.slave_relay_log_info;show slave status\G
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| Number_of_lines | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Sql_delay | Number_of_workers | Id | Channel_name |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
| 7 | /home/mysql/data/mysqldata1/relaylog/mysql-relay-bin.000011 | 1787845 | mysql-bin.000001 | 3158537 | 0 | 0 | 1 | |
+-----------------+-------------------------------------------------------------+---------------+------------------+----------------+-----------+-------------------+----+--------------+
1 row in set (0.00 sec)
2018-12-14T16:17:37.822661+08:00 1 [Note] Slave SQL thread for channel '' initialized, starting replication in log 'mysql-bin.000001'  at position 3158537, relay log '/home/mysql/data/mysqldata1/relaylog/mysql-relay-bin.000011' position: 1787845

观察两种情况下error.log日志中内容,发现:

  • Retrieved_Gtid_Set < Executed_Gtid_Set下,SQL线程按mysql.slave_relay_log_info表中记录的位置点信息(mysql-relay-bin.000017,186094)去starting replication时,发现对应的日志信息不存在(mysql-relay-bin.000017日志被我截断到185090),就继续执行下一个relaylog。因为Executed_Gtid_Set > Retrieved_Gtid_Set,UNION集合就是Executed_Gtid_Set,所以新生成的relaylog里拉取的第一个GTID是Executed_Gtid_Set的下一个GTID,SQL线程正常回放。

  • Retrieved_Gtid_Set > Executed_Gtid_Set下,error.log中有如下信息。因为在Executed_Gtid_Set小于Retrieved_Gtid_Set情况下,被截断的GTID还未被执行,所以SQL线程会尝试去执行,执行了发现事务不完整,会进行rollback;且MySQL启动后,这个不完整的事务会被放到last_received_GTID中,这样MySQL会根据UNION(@@global.gtid_executed, Retrieved_gtid_set - last_received_GTID)集合,IO线程会重新拉取这个不完整的事务,此时拉取后事务完整,SQL线程正常回放。

2018-12-14T16:17:38.020740+08:00 1 [Note] Slave SQL for channel '': Rolling back unfinished transaction (no COMMIT or ROLLBACK in relay log). A probable cause is partial transaction left on relay log because of restarting IO thread with auto-positioning protocol. Error_code: 0

| 问题

在GTID模式下,设置relay-log-recovery=0会不会影响从库的数据一致性?

并行复制下呢?

| 作者简介

韩杰 沃趣科技MySQL数据库工程师

熟悉mysql体系架构、主从复制,熟悉问题定位与解决。

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