MySQL Multi-Source Replication enables a replication slave to receive transactions from multiple sources simultaneously. Multi-source replication does not implement any conflict detection or resolution when applying the transactions, and those tasks are left to the application if required.
一、问题描述
多源复制，从库在开启复制之前，执行change replication filter replicate_ignore_db=(mysql); 按理应该忽略了mysql库的同步，为什么开启复制之后报错
Last_Error: Error 'Operation CREATE USER failed for 'repl'@'192.168.85.%'' on query. Default database: ''. Query: 'CREATE USER 'repl'@'192.168.85.%' IDENTIFIED WITH 'mysql_native_password' AS '*A424E797037BF97C19A2E88CF7891C5C2038C039''
首先怀疑使用了statement格式的日志(binlog_format='STATEMENT')，提问者没有说binlog_format。按照一贯思维，如果binlog_format='ROW'，它会检查变更数据所在的database是否匹配过滤选项；如果binlog_format='STATEMENT'，它会检查default database(use dbname)是否匹配过滤选项。
第一个推断：binlog_format='STATEMENT'，create user语句不是在mysql库下运行~
二、验证推断
2.1、create user
为了验证推断，在自己的一主一从环境(Gtid+Row)测试create user语句
# 从库复制过滤 mydba@192.168.85.133,3306 [(none)]> stop slave sql_thread; Query OK, 0 rows affected (0.01 sec) mydba@192.168.85.133,3306 [(none)]> change replication filter replicate_ignore_db=(mysql); Query OK, 0 rows affected (0.00 sec) mydba@192.168.85.133,3306 [(none)]> start slave sql_thread; Query OK, 0 rows affected (0.01 sec) # 主库Rotate日志 mydba@192.168.85.132,3306 [replcrash]> flush binary logs; Query OK, 0 rows affected (0.12 sec) mydba@192.168.85.132,3306 [replcrash]> show master status; +------------------+----------+--------------+------------------+----------------------------------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+----------------------------------------------+ | mysql-bin.000108 | 194 | | | 8ab82362-9c37-11e7-a858-000c29c1025c:1-69347 | +------------------+----------+--------------+------------------+----------------------------------------------+ 1 row in set (0.00 sec) mydba@192.168.85.132,3306 [replcrash]> select user,host from mysql.user; +---------------+--------------+ | user | host | +---------------+--------------+ | monitor | % | | mydba | 192.168.85.% | | repl | 192.168.85.% | | restoree | 192.168.85.% | | resolve | db%.zst.com | | mysql.session | localhost | | mysql.sys | localhost | | root | localhost | | zst | localhost | +---------------+--------------+ 9 rows in set (0.00 sec) # 从库Rotate日志 mydba@192.168.85.133,3306 [replcrash]> flush logs; Query OK, 0 rows affected (0.07 sec) mydba@192.168.85.133,3306 [replcrash]> show master status; +------------------+----------+--------------+------------------+------------------------------------------------------------------------------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+------------------------------------------------------------------------------------------+ | mysql-bin.000021 | 234 | | | 8ab82362-9c37-11e7-a858-000c29c1025c:1-69347, 93f69708-9c39-11e7-b7f8-000c2900c99c:1-284 | +------------------+----------+--------------+------------------+------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec) mydba@192.168.85.133,3306 [replcrash]> select user,host from mysql.user; +---------------+--------------+ | user | host | +---------------+--------------+ | monitor | % | | mydba | 192.168.85.% | | repl | 192.168.85.% | | restoree | 192.168.85.% | | resolve | db%.zst.com | | mysql.session | localhost | | mysql.sys | localhost | | root | localhost | | zst | localhost | +---------------+--------------+ 9 rows in set (0.02 sec) # 主库创建新用户(注意这里默认的db是replcrash) mydba@192.168.85.132,3306 [replcrash]> grant select on sakila.* to 'test'@'%' identified by '1234qwer'; Query OK, 0 rows affected, 1 warning (0.06 sec)
从库查看也创建了'test'@'%'用户，binlog_format='ROW'，怎么把过滤的mysql库中的create user给传到复制上去了？！
Note
Only DML statements can be logged using the row format. DDL statements are always logged as statements, even when binlog_format=ROW. All DDL statements are therefore always filtered according to the rules for statement-based replication. This means that you must select the default database explicitly with a USE statement in order for a DDL statement to be applied.
前面的grant语句在用户不存在时会创建用户，其实这类DCL语句也是记录为STATEMENT格式。我们注意grant语句默认的db是replcrash，并不是replicate_ignore_db选项中的mysql(虽然grant最终改变的对象是在mysql)，所以这条grant语句不会过滤。
如果我们使用：use mysql;grant select on sakila.* to 'test'@'%';默认db变成mysql，符合replicate_ignore_db选项中的mysql过滤条件，这条语句不会被应用到Slave~
如果我们使用：use replcrash;update mysql.user... 由于是ROW格式下的DML操作，语句影响的数据在mysql库，符合replicate_ignore_db选项中的mysql过滤条件，这条语句不会被应用到Slave~
2.2、update 授权表
测试update时忘记where条件，把整个mysql.user的密码给更新了
# 更新用户密码(本意只更新'test'@'%'用户) mydba@192.168.85.132,3306 [replcrash]> update mysql.user set authentication_string=password('1234'); Query OK, 10 rows affected, 1 warning (0.02 sec) Rows matched: 10 Changed: 10 Warnings: 1 mydba@192.168.85.132,3306 [replcrash]> show warnings; +---------+------+-------------------------------------------------------------------+ | Level | Code | Message | +---------+------+-------------------------------------------------------------------+ | Warning | 1681 | 'PASSWORD' is deprecated and will be removed in a future release. | +---------+------+-------------------------------------------------------------------+ 1 row in set (0.00 sec)
Changed: 10，再细看把整张表给更新，傻眼+++
# 主库Rotate日志 mydba@192.168.85.132,3306 [replcrash]> flush binary logs; # 查看主库用户信息 mydba@192.168.85.132,3306 [replcrash]> select user,host,authentication_string from mysql.user; +---------------+--------------+-------------------------------------------+ | user | host | authentication_string | +---------------+--------------+-------------------------------------------+ | root | localhost | *A4B6157319038724E3560894F7F932C8886EBFCF | | mysql.session | localhost | *A4B6157319038724E3560894F7F932C8886EBFCF | | mysql.sys | localhost | *A4B6157319038724E3560894F7F932C8886EBFCF | | repl | 192.168.85.% | *A4B6157319038724E3560894F7F932C8886EBFCF | | mydba | 192.168.85.% | *A4B6157319038724E3560894F7F932C8886EBFCF | | zst | localhost | *A4B6157319038724E3560894F7F932C8886EBFCF | | resolve | db%.zst.com | *A4B6157319038724E3560894F7F932C8886EBFCF | | restoree | 192.168.85.% | *A4B6157319038724E3560894F7F932C8886EBFCF | | monitor | % | *A4B6157319038724E3560894F7F932C8886EBFCF | | test | % | *A4B6157319038724E3560894F7F932C8886EBFCF | +---------------+--------------+-------------------------------------------+ 10 rows in set (0.00 sec) # 查看从库用户信息 mydba@192.168.85.133,3306 [replcrash]> select user,host,authentication_string from mysql.user; +---------------+--------------+-------------------------------------------+ | user | host | authentication_string | +---------------+--------------+-------------------------------------------+ | root | localhost | *A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5 | | mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | | mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | | repl | 192.168.85.% | *A424E797037BF97C19A2E88CF7891C5C2038C039 | | mydba | 192.168.85.% | *A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5 | | zst | localhost | *4E832DC6A6F24719A68C1242068114AA77CA60D0 | | resolve | db%.zst.com | *A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5 | | restoree | 192.168.85.% | *A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5 | | monitor | % | *1975D095AC033CAF4E1BF94F7202A9BBFEEB66F1 | | test | % | *0CB5F227B3E98395CA0C6F1427427E77ADF49F89 | +---------------+--------------+-------------------------------------------+ 10 rows in set (0.00 sec)
主库的密码update为同一个值，庆幸这些值不会应用到从库。此时查看复制正常，使用旧密码连接主库也正常
mydba@192.168.85.133,3306 [(none)]> pager cat | egrep 'Master_Log_File|Relay_Master_Log_File|Read_Master_Log_Pos|Exec_Master_Log_Pos|Running' PAGER set to 'cat | egrep 'Master_Log_File|Relay_Master_Log_File|Read_Master_Log_Pos|Exec_Master_Log_Pos|Running'' mydba@192.168.85.133,3306 [(none)]> show slave status\G Master_Log_File: mysql-bin.000108 Read_Master_Log_Pos: 3849 Relay_Master_Log_File: mysql-bin.000108 Slave_IO_Running: Yes Slave_SQL_Running: Yes Exec_Master_Log_Pos: 3849 Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates 1 row in set (0.00 sec) # 使用旧密码也还可以登录 C:\Users\Administrator>mysql -h192.168.85.132 -P3306 -umydba -p Enter password: ********* Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 33 Server version: 5.7.19-log MySQL Community Server (GPL)
2.3、binlog
grant+update语句在主库的binlog
[root@ZST1 logs]# mysqlbinlog -v --base64-output=decode-rows mysql-bin.000108 |more /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/; /*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/; DELIMITER /*!*/; # at 4 #171116 11:22:33 server id 1323306 end_log_pos 123 CRC32 0x4861f6e9 Start: binlog v 4, server v 5.7.19-log created 171116 11:22:33 # Warning: this binlog is either in use or was not closed properly. # at 123 #171116 11:22:33 server id 1323306 end_log_pos 194 CRC32 0x4bf5e123 Previous-GTIDs # 8ab82362-9c37-11e7-a858-000c29c1025c:1-69347 # at 194 ==================== GRANT操作对应的日志Start ==================== #171116 11:28:19 server id 1323306 end_log_pos 259 CRC32 0x965501a5 GTID last_committed=0 sequence_number=1 rbr_only=no SET @@SESSION.GTID_NEXT= '8ab82362-9c37-11e7-a858-000c29c1025c:69348'/*!*/; # at 259 #171116 11:28:19 server id 1323306 end_log_pos 493 CRC32 0xce77ebc8 Query thread_id=5 exec_time=0 error_code=0 use `replcrash`/*!*/; SET TIMESTAMP=1510802899/*!*/; SET @@session.pseudo_thread_id=5/*!*/; 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=1, @@session.auto_increment_offset=1/*!*/; /*!\C utf8 *//*!*/; SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=33/*!*/; SET @@session.lc_time_names=0/*!*/; SET @@session.collation_database=DEFAULT/*!*/; GRANT SELECT ON `sakila`.* TO 'test'@'%' IDENTIFIED WITH 'mysql_native_password' AS '*0CB5F227B3E98395CA0C6F1427427E77ADF49F89' /*!*/; ==================== GRANT操作对应的日志End ==================== # at 493 ==================== UPDATE操作对应的日志Start ==================== #171116 11:34:36 server id 1323306 end_log_pos 558 CRC32 0xaa76365b GTID last_committed=1 sequence_number=2 rbr_only=yes /*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/; SET @@SESSION.GTID_NEXT= '8ab82362-9c37-11e7-a858-000c29c1025c:69349'/*!*/; # at 558 #171116 11:34:36 server id 1323306 end_log_pos 635 CRC32 0x42f7046b Query thread_id=5 exec_time=0 error_code=0 SET TIMESTAMP=1510803276/*!*/; BEGIN /*!*/; # at 635 #171116 11:34:36 server id 1323306 end_log_pos 807 CRC32 0x2f85fb49 Table_map: `mysql`.`user` mapped to number 4 # at 807 #171116 11:34:36 server id 1323306 end_log_pos 3771 CRC32 0xadc9af46 Update_rows: table id 4 flags: STMT_END_F ### UPDATE `mysql`.`user` ### WHERE ### @1='localhost' ### @2='root' ### @3=2 ### @4=2 ### @5=2 ### @6=2 ### @7=2 ### @8=2 ### @9=2 ### @10=2 ### @11=2 ### @12=2 ### @13=2 ### @14=2 ### @15=2 ### @16=2 ### @17=2 ### @18=2 ### @19=2 ### @20=2 ### @21=2 ### @22=2 ### @23=2 ### @24=2 ### @25=2 ### @26=2 ### @27=2 ### @28=2 ### @29=2 ### @30=2 ### @31=2 ### @32=1 ### @33='' ### @34='' ### @35='' ### @36=0 ### @37=0 ### @38=0 ### @39=0 ### @40='mysql_native_password' ### @41='*A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5' ### @42=1 ### @43=1505715158 ### @44=NULL ### @45=1 ### SET ### @1='localhost' ### @2='root' ### @3=2 ### @4=2 ### @5=2 ### @6=2 ### @7=2 ### @8=2 ### @9=2 ### @10=2 ### @11=2 ### @12=2 ### @13=2 ### @14=2 ### @15=2 ### @16=2 ### @17=2 ### @18=2 ### @19=2 ### @20=2 ### @21=2 ### @22=2 ### @23=2 ### @24=2 ### @25=2 ### @26=2 ### @27=2 ### @28=2 ### @29=2 ### @30=2 ### @31=2 ### @32=1 ### @33='' ### @34='' ### @35='' ### @36=0 ### @37=0 ### @38=0 ### @39=0 ### @40='mysql_native_password' ### @41='*A4B6157319038724E3560894F7F932C8886EBFCF' ### @42=1 ### @43=1505715158 ### @44=NULL ### @45=1 ... ### UPDATE `mysql`.`user` ### WHERE ### @1='%' ### @2='test' ### @3=1 ### @4=1 ### @5=1 ### @6=1 ### @7=1 ### @8=1 ### @9=1 ### @10=1 ### @11=1 ### @12=1 ### @13=1 ### @14=1 ### @15=1 ### @16=1 ### @17=1 ### @18=1 ### @19=1 ### @20=1 ### @21=1 ### @22=1 ### @23=1 ### @24=1 ### @25=1 ### @26=1 ### @27=1 ### @28=1 ### @29=1 ### @30=1 ### @31=1 ### @32=1 ### @33='' ### @34='' ### @35='' ### @36=0 ### @37=0 ### @38=0 ### @39=0 ### @40='mysql_native_password' ### @41='*0CB5F227B3E98395CA0C6F1427427E77ADF49F89' ### @42=1 ### @43=1510802899 ### @44=NULL ### @45=1 ### SET ### @1='%' ### @2='test' ### @3=1 ### @4=1 ### @5=1 ### @6=1 ### @7=1 ### @8=1 ### @9=1 ### @10=1 ### @11=1 ### @12=1 ### @13=1 ### @14=1 ### @15=1 ### @16=1 ### @17=1 ### @18=1 ### @19=1 ### @20=1 ### @21=1 ### @22=1 ### @23=1 ### @24=1 ### @25=1 ### @26=1 ### @27=1 ### @28=1 ### @29=1 ### @30=1 ### @31=1 ### @32=1 ### @33='' ### @34='' ### @35='' ### @36=0 ### @37=0 ### @38=0 ### @39=0 ### @40='mysql_native_password' ### @41='*A4B6157319038724E3560894F7F932C8886EBFCF' ### @42=1 ### @43=1510802899 ### @44=NULL ### @45=1 # at 3771 #171116 11:34:36 server id 1323306 end_log_pos 3849 CRC32 0x752ce098 Query thread_id=5 exec_time=0 error_code=0 SET TIMESTAMP=1510803276/*!*/; COMMIT /*!*/; ==================== UPDATE操作对应的日志End ==================== # at 3849 #171116 12:41:52 server id 1323306 end_log_pos 3896 CRC32 0x7d007885 Rotate to mysql-bin.000109 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*/; [root@ZST1 logs]#
grant+update语句在从库的binlog
[root@ZST2 logs]# mysqlbinlog -v --base64-output=decode-rows mysql-bin.000021 |more /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/; /*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/; DELIMITER /*!*/; # at 4 #171116 11:24:29 server id 1333306 end_log_pos 123 CRC32 0x97380513 Start: binlog v 4, server v 5.7.19-log created 171116 11:24:29 # Warning: this binlog is either in use or was not closed properly. # at 123 #171116 11:24:29 server id 1333306 end_log_pos 234 CRC32 0x0e28801c Previous-GTIDs # 8ab82362-9c37-11e7-a858-000c29c1025c:496-69347, # 93f69708-9c39-11e7-b7f8-000c2900c99c:1-284 # at 234 ==================== 本地GRANT操作对应的日志Start(误操作) ==================== #171116 11:27:31 server id 1333306 end_log_pos 299 CRC32 0x237b657c GTID last_committed=0 sequence_number=1 rbr_only=no SET @@SESSION.GTID_NEXT= '93f69708-9c39-11e7-b7f8-000c2900c99c:285'/*!*/; # at 299 #171116 11:27:31 server id 1333306 end_log_pos 533 CRC32 0xf6511861 Query thread_id=3 exec_time=1 error_code=0 use `replcrash`/*!*/; SET TIMESTAMP=1510802851/*!*/; SET @@session.pseudo_thread_id=3/*!*/; 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=1, @@session.auto_increment_offset=1/*!*/; /*!\C utf8 *//*!*/; SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=33/*!*/; SET @@session.lc_time_names=0/*!*/; SET @@session.collation_database=DEFAULT/*!*/; GRANT SELECT ON `sakila`.* TO 'test'@'%' IDENTIFIED WITH 'mysql_native_password' AS '*0CB5F227B3E98395CA0C6F1427427E77ADF49F89' /*!*/; # at 533 #171116 11:28:07 server id 1333306 end_log_pos 598 CRC32 0x9631a777 GTID last_committed=1 sequence_number=2 rbr_only=no SET @@SESSION.GTID_NEXT= '93f69708-9c39-11e7-b7f8-000c2900c99c:286'/*!*/; # at 598 #171116 11:28:07 server id 1333306 end_log_pos 696 CRC32 0xd826df1b Query thread_id=3 exec_time=0 error_code=0 SET TIMESTAMP=1510802887/*!*/; drop user test@'%' /*!*/; ==================== 本地GRANT操作对应的日志End(误操作) ==================== # at 696 ==================== 复制GRANT操作对应的日志Start ==================== #171116 11:28:19 server id 1323306 end_log_pos 761 CRC32 0xa645c110 GTID last_committed=2 sequence_number=3 rbr_only=no SET @@SESSION.GTID_NEXT= '8ab82362-9c37-11e7-a858-000c29c1025c:69348'/*!*/; # at 761 #171116 11:28:19 server id 1323306 end_log_pos 995 CRC32 0x4924dc5a Query thread_id=5 exec_time=0 error_code=0 SET TIMESTAMP=1510802899/*!*/; GRANT SELECT ON `sakila`.* TO 'test'@'%' IDENTIFIED WITH 'mysql_native_password' AS '*0CB5F227B3E98395CA0C6F1427427E77ADF49F89' /*!*/; ==================== 复制GRANT操作对应的日志End ==================== # at 995 ==================== 复制UPDATE操作对应的日志Start ==================== #171116 11:34:36 server id 1323306 end_log_pos 1060 CRC32 0xab7a1a57 GTID last_committed=3 sequence_number=4 rbr_only=no SET @@SESSION.GTID_NEXT= '8ab82362-9c37-11e7-a858-000c29c1025c:69349'/*!*/; # at 1060 #171116 11:34:36 server id 1323306 end_log_pos 1137 CRC32 0x40d16e6e Query thread_id=5 exec_time=0 error_code=0 SET TIMESTAMP=1510803276/*!*/; BEGIN /*!*/; # at 1137 #171116 11:34:36 server id 1323306 end_log_pos 1215 CRC32 0x464fab8c Query thread_id=5 exec_time=0 error_code=0 SET TIMESTAMP=1510803276/*!*/; COMMIT /*!*/; ==================== 复制UPDATE操作对应的日志End ==================== 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*/; [root@ZST2 logs]#
当前环境下，主库上的binlog等效于从库上的relay-log，在主库的binlog中我们看到grant语句前面有use `replcrash`;从库在应用此relay-log时，不会过滤其后面的DDL/DCL语句，所以grant语句应用到从库，从库的binlog也看到对应记录，间接表明从库应用了grant语句。
主库的binlog中的UPDATE `mysql`.`user`语句影响的数据在mysql库下，从库应用此relay-log时，会过滤这些语句，所在update不会应用到从库，从库的binlog可以看到GTID_NEXT= '8ab82362-9c37-11e7-a858-000c29c1025c:69349'是一个空事务(BEGIN;COMMIT)
三、如何修复mysql.user
前面的update语句把主库的mysql.user密码更新错了，怎么还原到更新前的值？我自己的环境本身主、从mysql库是保持一致的，而且设置了复制过滤，update操作不会应用到从库，因此可以借助从库来修复主库的mysql.user
3.1、利用select into outfile + awk
# 数据导入导出限制目录 mydba@192.168.85.133,3306 [replcrash]> show variables like 'secure_file_priv'; +------------------+-------+ | Variable_name | Value | +------------------+-------+ | secure_file_priv | /tmp/ | +------------------+-------+ 1 row in set (0.03 sec) # 导出数据 mydba@192.168.85.133,3306 [replcrash]> select user,host,authentication_string from mysql.user into outfile '/tmp/mysql_user.sql'; Query OK, 10 rows affected (0.00 sec) # 生成rollback语句(注意单引号) [root@ZST2 logs]# cat /tmp/mysql_user.sql |awk '{print "update mysql.user set authentication_string='\''"$3"'\'' where user='\''"$1"'\'' and host='\''"$2"'\'';"}' >/tmp/roll_mysql_user.sql [root@ZST2 logs]# cat /tmp/roll_mysql_user.sql update mysql.user set authentication_string='*A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5' where user='root' and host='localhost'; update mysql.user set authentication_string='*THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE' where user='mysql.session' and host='localhost'; update mysql.user set authentication_string='*THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE' where user='mysql.sys' and host='localhost'; update mysql.user set authentication_string='*A424E797037BF97C19A2E88CF7891C5C2038C039' where user='repl' and host='192.168.85.%'; update mysql.user set authentication_string='*A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5' where user='mydba' and host='192.168.85.%'; update mysql.user set authentication_string='*4E832DC6A6F24719A68C1242068114AA77CA60D0' where user='zst' and host='localhost'; update mysql.user set authentication_string='*A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5' where user='resolve' and host='db%.zst.com'; update mysql.user set authentication_string='*A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5' where user='restoree' and host='192.168.85.%'; update mysql.user set authentication_string='*1975D095AC033CAF4E1BF94F7202A9BBFEEB66F1' where user='monitor' and host='%'; update mysql.user set authentication_string='*0CB5F227B3E98395CA0C6F1427427E77ADF49F89' where user='test' and host='%'; [root@ZST2 logs]#
将生成的脚本roll_mysql_user.sql应用到主库即可
3.2、MyISAM文件拷贝
# 拷贝文件 [root@ZST2 logs]# ll /data/mysql/mysql3306/data/mysql/user.* -rw-r-----. 1 mysql mysql 10816 Oct 30 15:06 /data/mysql/mysql3306/data/mysql/user.frm -rw-r-----. 1 mysql mysql 1260 Nov 16 11:28 /data/mysql/mysql3306/data/mysql/user.MYD -rw-r-----. 1 mysql mysql 4096 Nov 16 11:28 /data/mysql/mysql3306/data/mysql/user.MYI [root@ZST2 logs]# scp /data/mysql/mysql3306/data/mysql/user.* root@192.168.85.132:/data/mysql/mysql3306/data/mysql/ # 注意检查拷贝过去的文件chown # kill -HUP [root@ZST1 ~]# kill -HUP `pidof mysqld`
借助MyISAM引擎特性，注意修改文件属主信息
3.3、binlog2sql
解析主库上的binlog得到要闪回的位置，利用binlog2sql得到操作前的记录
[root@ZST1 ~]# cd /tools/binlog2sql/binlog2sql [root@ZST1 binlog2sql]# python binlog2sql.py --flashback -h192.168.85.132 -P3306 -umydba -p'mysql5719' -dmysql -tuser --start-file='mysql-bin.000108' --start-position=635 --stop-position=3849
mysql.user字段较多，update以ROW格式记录在binlog中，生成的闪回语句较长~
四、总结及疑问
4.1、总结
开篇问题的原因是，提问者在Master1、Master2没有指定default database的情况下创建了同名用户，在从库设置复制过滤后启动复制，Master1、Master2上的create user语句都应用到从库，导致第二次create user failed. 因此在操作DDL/DCL时记得USE DBNAME;
4.2、疑问
• update权限表，在什么时候生效？
内存结构中的权限信息何时被更新：FLUSH PRIVILEGES会强行让MySQL更新Load到内存中的权限信息；GRANT、REVOKE或者CREATE USER和DROP USER操作会直接更新内存中的权限信息；重启MySQL会让MySQL完全从grant tables中读取权限信息。
内存结构中的权限信息更新之后对已经连接上的用户何时生效：对于Global Level的权限信息的修改，仅仅只有更改之后新建连接才会用到，已经连接上的session并不会受到影响。对于Database Level的权限信息的修改，只有当客户端请求执行了“use database_name”命令之后，才会在重新校验中使用到新的权限信息。对于Table Level和Column Level的权限，在下一次需要使用到该权限的Query被请求的时候生效。
本例中update mysql.user是属于Global Level，只有在FLUSH PRIVILEGES后，新建连接才会要求使用新密码，当前已连接上的session不受影响。
• 系统库(information_schema、performance_schema、sys)会复制吗？
• 多源复制Master存在同名数据库，会出现什么情况？
对于同名数据库，Slave上的数据会错乱，因为Master1、Master2对同名数据库的变更全部会应用到Slave，一旦它们操作相同对象，就会出现交错。