环境：mysql一主一从架构，主库是mysql5.1，从库是mysql5.6；系统均为CentOS6.2

问题：

在主库上面执行的SQL语句

1.创建表

CREATETABLE`app_versions`(
`date`dateNOTNULL,
`app`char(16)NOTNULL,
`ver`char(16)NOTNULL,
`val`int(11)DEFAULT'0',
PRIMARYKEY(`date`,`app`,`ver`)
)ENGINE=MyISAMDEFAULTCHARSET=latin1;

2.创建用户并且给予权限

grant select on databasename.* to 'username'@'IPaddress' identified by 'password'

3.刷新权限信息

flush privileges

在主库上面执行完之后，在从库上面执行show slave status \G发现IO进程和SQL进程显示的都是NO，然后执行start slave IO_THREAD之后再次执行show slave status \G 发现IO进程是拉起来了的显示的是YES，之后再执行start slave SQL_THREAD进程，show slave status \G发现IO进程和SQL进程都是显示的NO，并且在从库的错误日志中可以获取得到:

在错误日志中可以很明显的看得到日志提示：

Missing system table mysql.proxies_pri;please run mysql_upgrade to create it

日志提示系统表mysql.proxies_pri不存在，需要执行mysql_upgrade，然后我自己google了一下，

发现大部分都是因为升级mysql之后没有执行mysql_upgrade导致的，但是我在主库上面根本就没有进

行任何的升级操作，在从库也是这个样子，然后网上的建议是mysql_upgrade升级修复一下。

mysql_upgrade主要作用是检测所有的表并且升级mysql这个系统库内所有的表，是进行在线升级的，所以并不会影响线上操作(PS:当然不包括有关mysql库的操作)。

Themysql.proxies_privtable contains information about proxy privileges. The table can be queried and although it is possible to directly update it, it is best to useGRANTfor setting privileges.

可以看到上述对于mysql.proxies_priv系统表的猜测，可以比较明显的看到这个表主要是用来管理

数据库用户权限信息的表，所以我猜测数据库很有可能卡在权限这块了，并且在从库中我在mysql.user这个表中并没有发现我之前grant创建的用户。这个时候我在从库上面设置了跳过一个事务：

set global sql_slave_skip_counter = 1(只是跳过一个事务，跳过之后归0)

之后我在重启start slave。slave恢复了正常，日志也能够正常的往里面写了。所以我猜想这个问题和

权限有关，假如需要验证的话，最好是在从库上面开启general log，并且在从库的binlog获取最新的事

务的信息并且根据获取的信息在relay log中继日志找到下一个事务是不是这个。

但是这个方案也是属于治标不治本，下次在执行grant操作的时候，可能还是会出现这个问题，所以还是最后使用mysql_upgrade

mysql_upgrade -uroot -p

[root@gitlab-test data]# mysql_upgrade -uroot -p

Enter password:

Looking for 'mysql' as: mysql

Looking for 'mysqlcheck' as: mysqlcheck

This installation of MySQL is already upgraded to 5.6.35, use --force if you still need to run mysql_upgrade

[root@gitlab-test data]# mysql_upgrade -uroot -p --force

Enter password:

Looking for 'mysql' as: mysql

Looking for 'mysqlcheck' as: mysqlcheck

Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/data/mysql/mysql.sock'

Warning: Using a password on the command line interface can be insecure.

Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/data/mysql/mysql.sock'

Warning: Using a password on the command line interface can be insecure.

mysql.columns_priv OK

mysql.dbOK

mysql.eventOK

mysql.func OK

mysql.general_log OK

mysql.help_categoryOK

mysql.help_keyword OK

mysql.help_relationOK

mysql.help_topicOK

mysql.innodb_index_statsOK

mysql.innodb_table_statsOK

mysql.ndb_binlog_index OK

mysql.pluginOK

mysql.proc OK

mysql.procs_privOK

mysql.proxies_priv_bak OK

mysql.servers OK

mysql.slave_master_infoOK

mysql.slave_relay_log_info OK

mysql.slave_worker_infoOK

mysql.slow_log OK

mysql.tables_priv OK

mysql.time_zoneOK

mysql.time_zone_leap_secondOK

mysql.time_zone_nameOK

mysql.time_zone_transition OK

mysql.time_zone_transition_typeOK

mysql.user OK

Running 'mysql_fix_privilege_tables'...

Warning: Using a password on the command line interface can be insecure.

Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/data/mysql/mysql.sock'

Warning: Using a password on the command line interface can be insecure.

Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/data/mysql/mysql.sock'

Warning: Using a password on the command line interface can be insecure.

core_test.test OK

data_test.test OK

gitlabhq_production.abuse_reports OK

gitlabhq_production.application_settingsOK

gitlabhq_production.audit_eventsOK

gitlabhq_production.broadcast_messages OK

gitlabhq_production.deploy_keys_projectsOK

gitlabhq_production.emails OK

gitlabhq_production.events OK

gitlabhq_production.forked_project_linksOK

gitlabhq_production.identities OK

gitlabhq_production.issues OK

gitlabhq_production.keysOK

gitlabhq_production.label_linksOK

gitlabhq_production.labels OK

gitlabhq_production.membersOK

gitlabhq_production.merge_request_diffsOK

gitlabhq_production.merge_requests OK

gitlabhq_production.milestones OK

gitlabhq_production.namespaces OK

gitlabhq_production.notes OK

gitlabhq_production.oauth_access_grantsOK

gitlabhq_production.oauth_access_tokensOK

gitlabhq_production.oauth_applications OK

gitlabhq_production.project_import_dataOK

gitlabhq_production.projectsOK

gitlabhq_production.protected_branches OK

gitlabhq_production.schema_migrations OK

gitlabhq_production.servicesOK

gitlabhq_production.snippetsOK

gitlabhq_production.subscriptions OK

gitlabhq_production.taggingsOK

gitlabhq_production.tagsOK

gitlabhq_production.users OK

gitlabhq_production.users_star_projectsOK

gitlabhq_production.web_hooks OK

OK