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  • Database基础(五):使用binlog日志、XtraBackup备份工具、MySQL AB复制

    一、使用binlog日志

    目标:

    利用binlog恢复库表,要求如下:

    1.     启用binlog日志
    2.     创建db1库tb1表,插入3条记录
    3.     删除tb1表中刚插入的3条记录
    4.     使用mysqlbinlog恢复删除的3条记录

    步骤:

    步骤一:启用binlog日志        //记录除了查询之外的SQL命令,默认未启用

    1)调整/etc/my.cnf配置,并重启服务

        [root@dbsvr1 ~]# vim  /etc/my.cnf
        [mysqld]
        .. ..
        log-bin-index=mysql-bin                              //启用二进制日志,并指定前缀
        server_id=1
        binlog_format=STATEMENT                               //在Mysql5.7中,binlog日志格式默认为ROW,但它不记录sql语句上下文相关信息。需要将binlog日志格式修改为STATEMENT
        .. ..
        [root@dbsvr1 ~]# systemctl  restart mysqld.service

    2)确认binlog日志文件

    新启用binlog后,每次启动MySQl服务都会新生成一份日志文件:

        [root@dbsvr1 ~]# ls /var/lib/mysql/mysql-bin.*
        /var/lib/mysql/mysql-bin.000001  /var/lib/mysql/mysql-bin.index

    其中mysql-bin.index文件记录了当前保持的二进制文件列表:

        [root@dbsvr1 ~]# cat /var/lib/mysql/mysql-bin.index
        ./mysql-bin.000001

    重启MySQL服务程序,或者执行SQL操作“FLUSH LOGS;”,会生成一份新的日志:

        [root@dbsvr1 ~]# ls /var/lib/mysql/mysql-bin.*
        /var/lib/mysql/mysql-bin.000001  /var/lib/mysql/mysql-bin.index
        /var/lib/mysql/mysql-bin.000002
        [root@dbsvr1 ~]# cat /var/lib/mysql/mysql-bin.index
        ./mysql-bin.000001
        ./mysql-bin.000002

    步骤二:利用binlog日志重做数据库操作

    1)执行数据库表添加操作

    创建db1·库tb1表,表结构自定义:

        mysql> CREATE DATABASE db1;
        Query OK, 1 row affected (0.05 sec)
        mysql> USE db1;
        Database changed
        mysql> CREATE TABLE tb1(
            -> id int(4) NOT NULL,name varchar(24)
            -> );
        Query OK, 0 rows affected (0.28 sec)

    插入3条表记录:

        mysql> INSERT INTO tb1 VALUES
            -> (1,'Jack'),
            -> (2,'Kenthy'),
            -> (3,'Bob');
        Query OK, 3 rows affected (0.12 sec)
        Records: 3  Duplicates: 0  Warnings: 0

    确认插入的表记录数据:

        mysql> SELECT * FROM tb1;
        +----+--------+
        | id | name   |
        +----+--------+
        |  1 | Jack   |
        |  2 | Kenthy |
        |  3 | Bob    |
        +----+--------+
        3 rows in set (0.00 sec)

    2)删除前一步添加的3条表记录

    执行删除所有表记录操作:

        mysql> DELETE FROM tb1;
        Query OK, 3 rows affected (0.09  sec)

    确认删除结果:

        mysql> SELECT * FROM tb1;
        Empty set (0.00 sec)

    步骤三:通过binlog日志恢复表记录

    binlog会记录所有的数据库、表更改操作,所以可在必要的时候重新执行以前做过的一部分数据操作,但对于启用binlog之前已经存在的库、表数据将不适用。

    根据上述“恢复被删除的3条表记录”的需求,应通过mysqlbinlog工具查看相关日志文件,找到删除这些表记录的时间点,只要恢复此前的SQL操作(主要是插入那3条记录的操作)即可。

    1)查看mysql-bin.000002日志内容

        [root@dbsvr1 ~]# mysqlbinlog /var/lib/mysql/mysql-bin.000002
        /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
        /*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
        DELIMITER /*!*/;
        # at 4
        #170412 12:05:32 server id 1  end_log_pos 123 CRC32 0x6d8c069c  Start: binlog v 4, server v 5.7.17-log created 170412 12:05:32 at startup
        # Warning: this binlog is either in use or was not closed properly.
        ROLLBACK/*!*/;
        BINLOG '
        jKftWA8BAAAAdwAAAHsAAAABAAQANS43LjE3LWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
        AAAAAAAAAAAAAAAAAACMp+1YEzgNAAgAEgAEBAQEEgAAXwAEGggAAAAICAgCAAAACgoKKioAEjQA
        AZwGjG0=
        '/*!*/;
        # at 123
        #170412 12:05:32 server id 1  end_log_pos 154 CRC32 0x17f50164  Previous-GTIDs
        # [empty]
        # at 154
        #170412 12:05:59 server id 1  end_log_pos 219 CRC32 0x4ba5a976  Anonymous_GTID  last_committed=0        sequence_number=1
        SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
        # at 219
        #170412 12:05:59 server id 1  end_log_pos 310 CRC32 0x5b66ae13  Query   thread_id=3     exec_time=0     error_code=0
        SET TIMESTAMP=1491969959/*!*/;
        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=8/*!*/;
        SET @@session.lc_time_names=0/*!*/;
        SET @@session.collation_database=DEFAULT/*!*/;
        CREATE DATABASE db1
        /*!*/;
        # at 310
        #170412 12:06:23 server id 1  end_log_pos 375 CRC32 0x2967cc28  Anonymous_GTID  last_committed=1        sequence_number=2
        SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
        # at 375
        #170412 12:06:23 server id 1  end_log_pos 502 CRC32 0x5de09aae  Query   thread_id=3     exec_time=0     error_code=0
        use `db1`/*!*/;
        SET TIMESTAMP=1491969983/*!*/;
        CREATE TABLE tb1(
        id int(4) NOT NULL,name varchar(24)
        )
        /*!*/;
        # at 502
        #170412 12:06:55 server id 1  end_log_pos 567 CRC32 0x0b8cd418  Anonymous_GTID  last_committed=2        sequence_number=3
        SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
        # at 567
        #170412 12:06:55 server id 1  end_log_pos 644 CRC32 0x7e8f2fa0  Query   thread_id=3     exec_time=0     error_code=0
        SET TIMESTAMP=1491970015/*!*/;
        BEGIN
        /*!*/;
        # at 644
        #170412 12:06:55 server id 1  end_log_pos 772 CRC32 0x4e3f728e  Query   thread_id=3     exec_time=0     error_code=0                            //插入表记录的起始时间点
        SET TIMESTAMP=1491970015/*!*/;
        INSERT INTO tb1 VALUES(1,'Jack'),(2,'Kenthy'), (3,'Bob')
        /*!*/;
        # at 772
        #170412 12:06:55 server id 1  end_log_pos 803 CRC32 0x6138b21f  Xid = 10
                                                              //确认事务的时间点
        COMMIT/*!*/;
        # at 803
        #170412 12:07:24 server id 1  end_log_pos 868 CRC32 0xbef3f472  Anonymous_GTID  last_committed=3        sequence_number=4
        SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
        # at 868
        #170412 12:07:24 server id 1  end_log_pos 945 CRC32 0x5684e92c  Query   thread_id=3     exec_time=0     error_code=0
        SET TIMESTAMP=1491970044/*!*/;
        BEGIN
        /*!*/;
        # at 945
        #170412 12:07:24 server id 1  end_log_pos 1032 CRC32 0x4c1c75fc         Query   thread_id=3     exec_time=0     error_code=0            //删除表记录的时间点
        SET TIMESTAMP=1491970044/*!*/;
        DELETE FROM tb1
        /*!*/;
        # at 1032
        #170412 12:07:24 server id 1  end_log_pos 1063 CRC32 0xccf549b2         Xid = 12
        COMMIT/*!*/;
        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*/;

    2) 执行指定Pos节点范围内的sql命令恢复数据

    根据上述日志分析,只要恢复从2014.01.12 20:12:14到2014.01.12 20:13:50之间的操作即可。可通过mysqlbinlog指定时间范围输出,结合管道交给msyql命令执行导入重做:

        [root@dbsvr1 ~]# mysqlbinlog
            --start-datetime="2017-04-12 12:06:55"
            --stop-datetime="2017-04-12 12:07:23"
            /var/lib/mysql/mysql-bin.000002 | mysql -u root -p
        Enter password:                                     //验证口令

    3)确认恢复结果

        mysql> SELECT * FROM db1.tb1;
        +----+--------+
        | id | name   |
        +----+--------+
        |  1 | Jack   |
        |  2 | Kenthy |
        |  3 | Bob    |
        +----+--------+
        3 rows in set (0.00 sec)

    二、XtraBackup备份工具

    目标:

    1.     安装XtraBackup软件包。
    2.     使用XtraBackup执行完整备份、增量备份。
    3.     准备数据恢复目录。

    步骤:

    步骤一:安装XtraBackup软件包

    1)了解软件包描述信息

        [root@dbsvr1 pub]# rpm -qpi percona-xtrabackup-24-2.4.6-2.el7.x86_64.rpm
        Name        : percona-xtrabackup-24
        Version     : 2.4.6
        Release     : 2.el7
        Architecture: x86_64
        Install Date: (not installed)
        Group       : Applications/Databases
        Size        : 32416340
        License     : GPLv2
        Signature   : DSA/SHA1, 2017年02月27日 星期一 20时28分17秒, Key ID 1c4cbdcdcd2efd2a
        Source RPM  : percona-xtrabackup-24-2.4.6-2.el7.src.rpm
        Build Date  : 2017年02月27日 星期一 20时27分21秒
        Build Host  : vps-centos7-x64-01.ci.percona.com
        Relocations : (not relocatable)
        URL         : http://www.percona.com/software/percona-xtrabackup
        Summary     : XtraBackup online backup for MySQL / InnoDB
        Description :
        Percona XtraBackup is OpenSource online (non-blockable) backup solution for InnoDB and XtraDB engines

    2)安装依赖包perl-DBD-MySQL perl-Digest-MD5 libev

    使用RHEL 7自带的即可,yum方式安装:

        [root@dbsvr1 pub]# yum -y install perl-DBD-MySQL perl-Digest-MD5
        libev使用网上找的rpm包 libev-4.15-1.el6.rf.x86_64.rpm   //该包由讲师提供
        [root@dbsvr1 pub]#rpm –ivh libev-4.15-1.el6.rf.x86_64.rpm

    如果未安装这些依赖包,则直接安装percona-xtrabackup时会报错:

        [root@dbsvr1 pub]# rpm -ivh percona-xtrabackup-24-2.4.6-2.el7.x86_64.rpm
            libev.so.4()(64bit) 被 percona-xtrabackup-24-2.4.6-2.el7.x86_64 需要
            perl(DBD::mysql) 被 percona-xtrabackup-24-2.4.6-2.el7.x86_64 需要
            perl(Digest::MD5) 被 percona-xtrabackup-24-2.4.6-2.el7.x86_64 需要

    3)安装percona-xtrabackup

        [root@dbsvr1 pub]#rpm -ivh percona-xtrabackup-*.rpm
        警告:percona-xtrabackup-24-2.4.6-2.el7.x86_64.rpm: 头V4 DSA/SHA1 Signature, 密钥 ID cd2efd2a: NOKEY
        准备中...                          ################################# [100%]
        正在升级/安装...
           1:percona-xtrabackup-24-2.4.6-2.el7################################# [ 33%]
           2:percona-xtrabackup-test-24-2.4.6-################################# [ 67%]
           3:percona-xtrabackup-24-debuginfo-2################################# [100%]

    4)确认安装的主要程序/脚本

        [root@dbsvr1 pub]# rpm -ql percona-xtrabackup-24-2.4.6-2.el7.x86_64
        /usr/bin/innobackupex
        /usr/bin/xbcloud
        /usr/bin/xbcloud_osenv
        /usr/bin/xbcrypt
        /usr/bin/xbstream
        /usr/bin/xtrabackup
        /usr/share/doc/percona-xtrabackup-24-2.4.6
        /usr/share/doc/percona-xtrabackup-24-2.4.6/COPYING
        /usr/share/man/man1/innobackupex.1.gz
        /usr/share/man/man1/xbcrypt.1.gz
        /usr/share/man/man1/xbstream.1.gz
        /usr/share/man/man1/xtrabackup.1.gz

    步骤二:使用XtraBackup执行数据库备

    --host 主机名

    --port 3306

    --user 用户名

    --password 密码

    --databases="库名"

    --databases="库1 库2"

    --databases="库.表"

    --no-timestamp 不用日期命名备份文件存储的子目录,使用备份的数据库名做备份目录名

    --no-timestmap 不使用日期命名备份目录名

    1)做一个完整备份

    默认情况下,备份文件存储的子目录会用日期命名,

    innobackupex作为客户端工具,以mysql协议连入mysqld,将数据备份到/backup文件夹:

        [root@dbsvr1 ~]# innobackupex --user=root --password=123456 /backup/mysql –no-timestamp
        170425 11:05:44 innobackupex: Starting the backup operation
        IMPORTANT: Please check that the backup run completes successfully.
                   At the end of a successful backup run innobackupex
                   prints "completed OK!".
        Unrecognized character x01; marked by <-- HERE after <-- HERE near column 1 at - line 1374.
        170425 11:05:45 Connecting to MySQL server host: localhost, user: root, password: set, port: not set, socket: not set
        Using server version 5.7.17
        innobackupex version 2.4.6 based on MySQL server 5.7.13 Linux (x86_64) (revision id: 8ec05b7)
        xtrabackup: uses posix_fadvise().
        xtrabackup: cd to /var/lib/mysql
        xtrabackup: open files limit requested 0, set to 1024
        xtrabackup: using the following InnoDB configuration:
        xtrabackup:   innodb_data_home_dir = .
        xtrabackup:   innodb_data_file_path = ibdata1:12M:autoextend
        xtrabackup:   innodb_log_group_home_dir = ./
        xtrabackup:   innodb_log_files_in_group = 2
        xtrabackup:   innodb_log_file_size = 50331648
        InnoDB: Number of pools: 1
        170425 11:05:45 >> log scanned up to (2543893)
        xtrabackup: Generating a list of tablespaces
        InnoDB: Allocated tablespace ID 2 for mysql/plugin, old maximum was 0
        170425 11:05:45 [01] Copying ./ibdata1 to /backup/ibdata1
        170425 11:05:45 [01]        ...done
        170425 11:05:46 [01] Copying ./mysql/plugin.ibd to /backup/mysql/plugin.ibd
        170425 11:05:46 [01]        ...done
        170425 11:05:46 [01] Copying ./mysql/servers.ibd to /backup/mysql/servers.ibd
        170425 11:05:46 [01]        ...done
        170425 11:05:46 [01] Copying ./mysql/help_topic.ibd to /backup/mysql/help_topic.ibd
        170425 11:05:46 [01]        ...done
        170425 11:05:46 >> log scanned up to (2543893)
        .. ..
        170425 11:06:00 [01] Copying ./sys/x@0024waits_global_by_latency.frm to /backup/sys/x@0024waits_global_by_latency.frm
        170425 11:06:00 [01]        ...done
        170425 11:06:00 [01] Copying ./sys/session_ssl_status.frm to /backup/sys/session_ssl_status.frm
        170425 11:06:00 [01]        ...done
        170425 11:06:00 [01] Copying ./db1/db.opt to /backup/db1/db.opt
        170425 11:06:00 [01]        ...done
        170425 11:06:00 [01] Copying ./db1/tb1.frm to /backup/db1/tb1.frm
        170425 11:06:00 [01]        ...done
        170425 11:06:00 Finished backing up non-InnoDB tables and files
        170425 11:06:00 Executing FLUSH NO_WRITE_TO_BINLOG ENGINE LOGS...
        xtrabackup: The latest check point (for incremental): '2543884'
        xtrabackup: Stopping log copying thread.
        .170425 11:06:00 >> log scanned up to (2543893)
        170425 11:06:00 Executing UNLOCK TABLES
        170425 11:06:00 All tables unlocked
        170425 11:06:00 [00] Copying ib_buffer_pool to /backup/ib_buffer_pool
        170425 11:06:00 [00]        ...done
        170425 11:06:00 Backup created in directory '/backup/'
        170425 11:06:00 [00] Writing backup-my.cnf
        170425 11:06:00 [00]        ...done
        170425 11:06:00 [00] Writing xtrabackup_info
        170425 11:06:00 [00]        ...done
        xtrabackup: Transaction log of lsn (2543884) to (2543893) was copied.
        170425 11:06:01 completed OK

    确认备份好的文件数据:

        [root@dbsvr1 ~]#ls /backup/mysql
        backup-my.cnf  ib_buffer_pool  mysql      sys                   xtrabackup_info
        db1  ibdata1      performance_schema  xtrabackup_checkpoints  xtrabackup_logfile

    2)做一个增量备份(基于前一步的完整备份)

    随意做一些新增或更改库表的操作,比如在db1库中新建一个mytb的表:

        mysql> USE db1;
        Database changed
        mysql> CREATE TABLE mytb(id int(4), name varchar(24));
        Query OK, 0 rows affected (0.38 sec)
        mysql> INSERT INTO tb1 VALUES
            -> (1,'bon'),
            -> (2,'bo'),
        Query OK, 2 rows affected (0.12 sec)
        Records: 2  Duplicates: 0  Warnings: 0
        mysql> SELECT * FROM tb1;
        +------+------+
        | id   | name |
        +------+------+
        |    1 | bob  |
        |    2 | bo   |
        +------+------+
        2 rows in set (0.00 sec)

    以前一次保存到/backup的完整备份为基础,做一个增量备份,保存到/incr01/,指定增量备份参照的基本目录(完整备份目录)需要用到选项--incremental-basedir。相关操作如下:

        [root@dbsvr1 ~]# innobackupex  --user=root --password=123456 --incremental /incr01 --incremental-basedir=/backup/mysql --no-timestamp
        170425 11:30:14 innobackupex: Starting the backup operation
        IMPORTANT: Please check that the backup run completes successfully.
                   At the end of a successful backup run innobackupex
                   prints "completed OK!".
        Unrecognized character x01; marked by <-- HERE after <-- HERE near column 1 at - line 1374.
        170425 11:30:14 Connecting to MySQL server host: localhost, user: root, password: set, port: not set, socket: not set
        Using server version 5.7.17
        innobackupex version 2.4.6 based on MySQL server 5.7.13 Linux (x86_64) (revision id: 8ec05b7)
        incremental backup from 2543884 is enabled.
        xtrabackup: uses posix_fadvise().
        xtrabackup: cd to /var/lib/mysql
        xtrabackup: open files limit requested 0, set to 1024
        xtrabackup: using the following InnoDB configuration:
        xtrabackup:   innodb_data_home_dir = .
        xtrabackup:   innodb_data_file_path = ibdata1:12M:autoextend
        xtrabackup:   innodb_log_group_home_dir = ./
        xtrabackup:   innodb_log_files_in_group = 2
        xtrabackup:   innodb_log_file_size = 50331648
        InnoDB: Number of pools: 1
        170425 11:30:14 >> log scanned up to (2549933)
        xtrabackup: Generating a list of tablespaces
        InnoDB: Allocated tablespace ID 2 for mysql/plugin, old maximum was 0
        xtrabackup: using the full scan for incremental backup
        170425 11:30:15 [01] Copying ./ibdata1 to /incr01/ibdata1.delta
        170425 11:30:15 [01]        ...done
        170425 11:30:15 >> log scanned up to (2549933)
        170425 11:30:15 [01] Copying ./mysql/plugin.ibd to /incr01/mysql/plugin.ibd.delta
        170425 11:30:15 [01]        ...done
        ... ...
        170425 11:30:35 Executing UNLOCK TABLES
        170425 11:30:35 All tables unlocked
        170425 11:30:35 [00] Copying ib_buffer_pool to /incr01/ib_buffer_pool
        170425 11:30:35 [00]        ...done
        170425 11:30:35 Backup created in directory '/incr01/'
        170425 11:30:35 [00] Writing backup-my.cnf
        170425 11:30:35 [00]        ...done
        170425 11:30:35 [00] Writing xtrabackup_info
        170425 11:30:35 [00]        ...done
        xtrabackup: Transaction log of lsn (2549924) to (2549933) was copied.
        170425 11:30:35 completed OK!

    确认备份好的文件数据:

        [root@dbsvr1 ~]# ls /incr01/
        backup-my.cnf  ib_buffer_pool  ibdata1.meta  performance_schema  xtrabackup_checkpoints  xtrabackup_logfile
        db1            ibdata1.delta   mysql         sys

    对比完整备份、增量备份的大小:

        [root@dbsvr1 ~]# du -sh /backup/mysql /incr01/
        142M    /backup/mysql                              //完整备份的大小
        3.5M    /incr01/                              //增量备份的大小

    步骤三:准备用于恢复的数据库目录

    通过XtraBackup工具备份的数据库目录,若要恢复到另一个MySQL服务器,需要先做一个“--apply-log --redo-only ”的准备操作。

    1)准备恢复“完整备份”

    完成准备以后,最终/backup可用来重建MySQL服务器。这种情况下,需要先做一个“--apply-log --redo-only ”的准备操作,以确保数据一致性:

        [root@dbsvr1 ~]#innobackupex  --user=root --password=123456 --apply-log  --redo-only /backup/mysql      //对备份数据库的位置做日志回读操作
        170425 11:42:19 innobackupex: Starting the apply-log operation
        IMPORTANT: Please check that the apply-log run completes successfully.
                   At the end of a successful apply-log run innobackupex
                   prints "completed OK!".
        innobackupex version 2.4.6 based on MySQL server 5.7.13 Linux (x86_64) (revision id: 8ec05b7)
        xtrabackup: cd to /backup/mysql
        xtrabackup: This target seems to be already prepared.
        InnoDB: Number of pools: 1
        xtrabackup: notice: xtrabackup_logfile was already used to '--prepare'.
        xtrabackup: using the following InnoDB configuration for recovery:
        xtrabackup:   innodb_data_home_dir = .
        xtrabackup:   innodb_data_file_path = ibdata1:12M:autoextend
        xtrabackup:   innodb_log_group_home_dir = .
        xtrabackup:   innodb_log_files_in_group = 2
        xtrabackup:   innodb_log_file_size = 50331648
        xtrabackup: using the following InnoDB configuration for recovery:
        xtrabackup:   innodb_data_home_dir = .
        xtrabackup:   innodb_data_file_path = ibdata1:12M:autoextend
        xtrabackup:   innodb_log_group_home_dir = .
        xtrabackup:   innodb_log_files_in_group = 2
        xtrabackup:   innodb_log_file_size = 50331648
        xtrabackup: Starting InnoDB instance for recovery.
        xtrabackup: Using 104857600 bytes for buffer pool (set by --use-memory parameter)
        InnoDB: PUNCH HOLE support available
        InnoDB: Mutexes and rw_locks use GCC atomic builtins
        InnoDB: Uses event mutexes
        InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
        InnoDB: Compressed tables use zlib 1.2.7
        InnoDB: Number of pools: 1
        InnoDB: Not using CPU crc32 instructions
        InnoDB: Initializing buffer pool, total size = 100M, instances = 1, chunk size = 100M
        InnoDB: Completed initialization of buffer pool
        InnoDB: page_cleaner coordinator priority: -20
        InnoDB: Highest supported file format is Barracuda.
        xtrabackup: starting shutdown with innodb_fast_shutdown = 1
        InnoDB: Starting shutdown...
        InnoDB: Shutdown completed; log sequence number 2544177
        InnoDB: Number of pools: 1
        170425 11:42:20 completed OK!

    准备恢复“增量备份”

        [root@dbsvr1 ~]#innobackupex  --user=root --password=123456 --apply-log  --redo-only /backup/mysql  --incremental-dir=/incr01
        170425 11:42:55 innobackupex: Starting the apply-log operation
        IMPORTANT: Please check that the apply-log run completes successfully.
                   At the end of a successful apply-log run innobackupex
                   prints "completed OK!".
        innobackupex version 2.4.6 based on MySQL server 5.7.13 Linux (x86_64) (revision id: 8ec05b7)
        incremental backup from 2543884 is enabled.
        xtrabackup: cd to /backup/
        xtrabackup: This target seems to be already prepared with --apply-log-only.
        InnoDB: Number of pools: 1
        xtrabackup: xtrabackup_logfile detected: size=8388608, start_lsn=(2549924)
        xtrabackup: using the following InnoDB configuration for recovery:
        xtrabackup:   innodb_data_home_dir = .
        xtrabackup:   innodb_data_file_path = ibdata1:12M:autoextend
        xtrabackup:   innodb_log_group_home_dir = /incr01/
        xtrabackup:   innodb_log_files_in_group = 1
        xtrabackup:   innodb_log_file_size = 8388608
        xtrabackup: Generating a list of tablespaces
        InnoDB: Allocated tablespace ID 2 for mysql/plugin, old maximum was 0
        xtrabackup: page size for /incr01//ibdata1.delta is 16384 bytes
        Applying /incr01//ibdata1.delta to ./ibdata1...
        ... ...
        170425 11:43:09 [01] Copying /incr01/performance_schema/global_status.frm to ./performance_schema/global_status.frm
        170425 11:43:09 [01]        ...done
        170425 11:43:09 [01] Copying /incr01/performance_schema/session_status.frm to ./performance_schema/session_status.frm
        170425 11:43:09 [01]        ...done
        170425 11:43:09 [00] Copying /incr01//xtrabackup_info to ./xtrabackup_info
        170425 11:43:09 [00]        ...done
        170425 11:43:10 completed OK!

    2)关闭mysql服务,并将/var/lib/mysql/下的文件删除,假设数据被删除。

        [root@dbsvr1 ~]#systemctl  stop  mysqld
        [root@dbsvr1 ~]#rm -rf /var/lib/mysql

    3)恢复“完整备份+增量备份”

    完成准备以后,最终仍然是/backup用来重建MySQL服务器,但这种情况下需提前合并相关增量备份的数据

        [root@dbsvr1 ~]# mkdir /var/lib/mysql       //注意恢复数据库前,重建/var/lib/mysql数据库目录,因为刚才为了做假设将目录删掉了;后面测试发现这个目录在innobackupex命令下会自动创建,所以这步骤可以没有
        [root@dbsvr1 ~]# chown -R mysql:mysql /var/lib/mysql     //创建的目录需要归档为mysql用户和mysql组,否则启动会报错,保证mysql用户对此目录的权限;如果上面没创建目录这步骤可以不要,后面等innobackupex恢复命令执行后(自动创建这个目录),再归档

        [root@dbsvr1 ~]# innobackupex --user=root --password=123456 --copy-back  /backup/mysql     //将backup/mysql里面的数据恢复回来
        ... ...
        170425 11:51:39 [01] Copying ./performance_schema/global_status.frm to /var/lib/mysql/performance_schema/glo.frm
        170425 11:51:39 [01]        ...done
        170425 11:51:39 [01] Copying ./performance_schema/session_status.frm to /var/lib/mysql/performance_schema/seus.frm
        170425 11:51:39 [01]        ...done
        170425 11:51:39 [01] Copying ./ib_buffer_pool to /var/lib/mysql/ib_buffer_pool
        170425 11:51:39 [01]        ...done
        170425 11:51:39 [01] Copying ./ibtmp1 to /var/lib/mysql/ibtmp1
        170425 11:51:39 [01]        ...done
        170425 11:51:39 [01] Copying ./xtrabackup_info to /var/lib/mysql/xtrabackup_info
        170425 11:51:39 [01]        ...done
        170425 11:51:39 completed OK!

    4)修改/var/lib/mysql/下文件属主与属组,查看数据:

    恢复后,/var/lib/mysql下文件属组与属主皆为root,需要更改为mysql

        [root@dbsvr1 ~]#chown -R mysql:mysql /var/lib/mysql      //chown -R 递归归属文件属性,这步骤最好放在第三步骤操作
        [root@dbsvr1 ~]#systemctl  start mysqld.service
        [root@dbsvr1 ~]#mysql -uroot -p12345678 -e "select * from db1.tb1"
        mysql: [Warning] Using a password on the command line interface can be insecure.
        +------+------+
        | id   | name |
        +------+------+
        |    1 | bob  |
        |    2 | bo   |
        +------+------+

    三、MySQL AB复制

    目标:

    1.     配置2台MySQL服务器,实现 主-->从 同步。
    2.     其中Master服务器允许SQL查询、写入,Slave服务器只允许SQL查询

    方案:

    使用2台RHEL 6虚拟机,如下图所示。其中192.168.4.10是MySQL主服务器,负责提供同步源;另一台192.168.4.20作为MySQL从服务器, 通过调取主服务器上的binlog日志,在本地重做对应的库、表,实现与主服务器的AB复制(同步)。

            

    提前为两台MySQL服务器安装好MySQL-server、MySQL-Client软件包,并为数据库用户root修改密码;Linux客户机上则只需安装MySQL-Client软件包即可。

    步骤:

    步骤一:初始化现有库

    为了在启用binlog日志及同步之前保持主、从库的一致性,建议进行初始化——备份主服务器上现有的库,然后导入到从服务器上。

    当现有库、表都采用MyISAM引擎时,可执行离线备份、恢复,这样更有效率;否则,可通过mysqldump等工具来实现库的导出、导入。

    1)备份MySQL Master(192.168.4.10)上现有的库

    如果服务器已经启用binlog,建议对日志做一次重置,否则可忽略:

        [root@dbsvr1 ~]# mysql -u root -p       //可以这里-p后面紧跟密码,即可直接进入数据库
        Enter password:                                  //以数据库用户root登入
        .. ..
        mysql> RESET MASTER;                              //重置binlog日志
        Query OK, 0 rows affected (0.06 sec)
        mysql> quit                                      //退出mysql> 环境
        Bye

    以备份mysql库、sys库为例,导出操作如下:

        [root@dbsvr1 ~]# mysqldump -u root -p --all-databases  > /root/mytest.sql     //可以这里-p后面紧跟密码
        Enter password:                                      //验证口令
        [root@dbsvr1 ~]# ls -lh /root/mytest.sql              //确认备份结果
        -rw-r--r--. 1 root root 777172 4月  23 12:21 /root/mytest.sql

    2)在MySQL Slave(192.168.4.20)上导入备份的库

    先清理目标库,避免导入时冲突。主要是采用InnoDB引擎的库,授权库mysql多采用MyISAM引擎,可不做清理。

        [root@dbsvr2 ~]# mysql -u root -p
        Enter password:                                  //以数据库用户root登入
        .. ..
        mysql> DROP DATABASE test;                          //删除test库
        Query OK, 0 rows affected (0.03 sec)
        mysql> quit                                      //退出mysql> 环境
        Bye

    使用scp工具下载备份文件:

        [root@dbsvr1 ~]# scp /root/mytest.sql  root@192.168.4.20:/
        root@dbsvr1's password:                          //验证对方系统用户root的口令
        mytest.sql                                  100%  759KB 759.0KB/s   00:00
        [root@dbsvr1 ~]# ls -lh mytest.sql              //确认下载结果
        -rw-r--r--. 1 root root 759K 4月  23 12:22 /mytest.sql

    执行导入操作:

        [root@dbsvr2 ~]# mysql -u root -p < /mytest.sql
        Enter password:                                  //验证口令

    导入成功后,可重新登入 mysql> 环境,确认清理的目标库已恢复:    mysql> show databases;
        +--------------------+
        | Database           |
        +--------------------+
        | information_schema |
        | mysql              |
        | performance_schema |
        | sys                 |                          
        +--------------------+
        4 rows in set (0.00 sec)

    步骤二:配置MySQL Master(主服务器,192.168.4.10)

    1)修改/etc/my.cnf配置,重新启动MySQL服务程序

    指定服务器ID号、允许日志同步:

        [root@dbsvr1 mysql]# vim /etc/my.cnf
        [mysqld]
        log_bin=dbsvr1-bin                      //启用binlog日志,并指定文件名前缀
        server_id = 10                          //指定服务器ID号
        ......

    重启mysql服务:

        [root@dbsvr1 ~]# systemctl  restart mysqld.service

    2)新建一个备份用户,授予复制权限

    需要的权限为REPLICATION SLAVE,允许其从Slave服务器访问:

        mysql> GRANT REPLICATION SLAVE ON *.* TO 'replicater'@'192.168.4.%' IDENTIFIED BY 'pwd123';
        Query OK, 0 rows affected, 1 warning (0.09 sec)

    3)检查Master服务器的同步状态

    在已经初始化现有库的情况下,查看MASTER状态,记录下当前的日志文件名、偏移的位置(下面SLAVE发起复制时需要用到):

        mysql> SHOW MASTER STATUSG
        *************************** 1. row ***************************
                     File: dbsvr1-bin.000001              //记住当前的日志文件名
                 Position: 154                             //记住当前的位置
             Binlog_Do_DB:
         Binlog_Ignore_DB:
        Executed_Gtid_Set:
        1 row in set (0.00 sec)

    步骤三:配置MySQL Slave(从服务器,192.168.4.20)

    1)修改/etc/my.cnf配置,重新启动MySQL服务程序

    指定服务器ID号、允许日志同步:    [root@dbsvr2 ~]# vim /etc/my.cnf
        [mysqld]
        log_bin=dbsvr2-bin                      //启动SQL日志,并指定文件名前缀
        server_id = 20                          //指定服务器ID号,不要与Master的相同
        .. ..

    在生产环境中,还可以根据需要设置更详细的同步选项。比如,指定当主、从网络中断时的重试超时时间(slave-net-timeout=60 )等,具体可参考MySQL手册。

    配置完成后,重启mysql服务:

        [root@dbsvr2 ~]# systemctl  restart mysqld.service

    通过CHANGE MASTER语句指定MASTER服务器的IP地址、同步用户名/密码、起始日志文件、偏移位置(参考MASTER上的状态输出):

        mysql> CHANGE MASTER TO MASTER_HOST='192.168.4.10',
            -> MASTER_USER='replicater',
            -> MASTER_PASSWORD='pwd123',
            -> MASTER_LOG_FILE='dbsvr1-bin.000002',      //对应Master的日志文件
            -> MASTER_LOG_POS=334;                          //对应Master的日志偏移位置
        Query OK, 0 rows affected, 2 warnings (0.12 sec)

    然后执行START SLAVE(较早版本中为SLAVE START)启动复制:

        mysql> START SLAVE;                              //启动复制
        Query OK, 0 rows affected (0.00 sec)

    注意:一旦启用SLAVE复制,当需要修改MASTER信息时,应先执行STOP SLAVE停止复制,然后重新修改、启动复制。

    通过上述连接操作,MASTER服务器的设置信息自动存为master.info文件,以后每次MySQL服务程序时会自动调用并更新,无需重复设置。查看master.info文件的开头部分内容,可验证相关设置:

        [root@dbsvr2 ~]# ls -lh /var/lib/mysql/master.info
        -rw-r-----. 1 mysql mysql 132 4月  23 12:06 /var/lib/mysql/master.info
        [root@dbsvr2 ~]# head /var/lib/mysql/master.info     //注意这个文件是保存在slave服务器的
        25
        dbsvr1-bin.000001
        154
        192.168.4.10
        replicater
        pwd123
        3306
        60
        0

    2)检查Slave服务器的同步状态

    通过SHOW SLAVE STATUS语句可查看从服务器状态,确认其中的IO线程、SQL线程正常运行,才能成功同步:

        mysql> SHOW SLAVE STATUSG
        Slave_IO_State: Waiting for master to send event
                          Master_Host: 192.168.4.1
                          Master_User: replicater
                          Master_Port: 3306
                        Connect_Retry: 60
                      Master_Log_File: dbsvr1-bin.000001
                  Read_Master_Log_Pos: 154
                       Relay_Log_File: db2-relay-bin.000003
                        Relay_Log_Pos: 321
                Relay_Master_Log_File: dbsvr1-bin.000001
                     Slave_IO_Running: Yes             //IO线程应该已运行
                    Slave_SQL_Running: Yes             //SQL线程应该已运行
                      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: 154
                      Relay_Log_Space: 2490
                      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: 10
                          Master_UUID: 2d4d8a11-27b7-11e7-ae78-52540055c180
                     Master_Info_File: /var/lib/mysql/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:
                    Executed_Gtid_Set:
                        Auto_Position: 0
                 Replicate_Rewrite_DB:
                         Channel_Name:
                   Master_TLS_Version:
        1 row in set (0.00 sec)

    若START SLAVE直接报错失败,请检查CHANGE MASTER相关设置是否有误,纠正后再重试;若IO线程或SQL线程有一个为“No”,则应检查服务器的错误日志,分析并排除故障后重启主从复制。

    步骤四:测试主从同步效果

    1)在Master上操作数据库、表、表记录

    新建newdb库、newtable表,随意插入几条表记录:

        mysql> CREATE DATABASE newdb;                          //新建库newdb
        Query OK, 1 row affected (0.17 sec)
        mysql> USE newdb;                                      //切换到newdb库
        Database changed
        mysql> CREATE TABLE newtable(id int(4));              //新建newtable表
        Query OK, 0 rows affected (0.46 sec)
        mysql> INSERT INTO newtable VALUES(1234),(5678);      //插入2条表记录
        Query OK, 2 rows affected (0.24 sec)
        Records: 2  Duplicates: 0  Warnings: 0
        mysql> SELECT * FROM newtable;                         //确认表数据
        +------+
        | id   |
        +------+
        | 1234 |
        | 5678 |
        +------+
        2 rows in set (0.00 sec)

    2)在Slave上确认自动同步的结果

    直接切换到newdb库,并查询newtable表的记录,应该与Master上的一样,这才说明主从同步已经成功生效:

        mysql> USE newdb;                                      //直接切换到newdb库
        Reading table information for completion of table and column names
        You can turn off this feature to get a quicker startup with -A
        Database changed
        mysql> SELECT * FROM newtable;                      //输出表记录
        +------+
        | id   |
        +------+
        | 1234 |
        | 5678 |
        +------+
        2 rows in set (0.02 sec)

    3)在Master服务器上可查看Slave主机的信息

        mysql> SHOW SLAVE HOSTS;
        +-----------+------+------+-----------+--------------------------------------+
        | Server_id | Host | Port | Master_id | Slave_UUID                           |
        +-----------+------+------+-----------+--------------------------------------+
        |         2 |      | 3306 |        10 | 512cf7c1-27c4-11e7-8f4b-5254007b030b |
        +-----------+------+------+-----------+--------------------------------------+
        1 row in set (0.00 sec)

    步骤五:将Slave服务器设为只读

    一般来说,为了避免写入冲突,采用主、从复制结构时,不应该允许用户从Slave执行数据库写入操作,这样会导致双方数据的不一致性。

    正因为如此,我们可以把Slave数据库限制为只读模式,这种情况下有SUPER权限的用户和SLAVE同步线程才能写入。相关验证操作及效果可参考以下过程。

    1)新建一个测试用户rwuser(不能用root测试)

    在Master上建立即可,会自动同步到Slave上:

        mysql> GRANT all ON newdb.* TO rwuser@localhost IDENTIFIED BY '1234567';
        Query OK, 0 rows affected, 1 warning (0.09 sec)

    2)未启用只读前,验证从Slave写入

    在Slave上以rwuser登入(不要用root哦):

        [root@dbsvr2 ~]# mysql -u rwuser -p
        Enter password:
        Welcome to the MySQL monitor.  Commands end with ; or g.
        Your MySQL connection id is 30
        Server version: 5.7.17-log MySQL Community Server (GPL)
        Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
        Oracle is a registered trademark of Oracle Corporation and/or its
        affiliates. Other names may be trademarks of their respective
        owners.
        Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
        mysql>

    然后向newdb库中新建一个booker表:

        mysql> USE newdb;                                  //切换到newdb库
        Reading table information for completion of table and column names
        You can turn off this feature to get a quicker startup with -A
        Database changed
        mysql> CREATE TABLE booker(id int(12));          //成功创建booker表
        Query OK, 0 rows affected (0.64 sec)

    在Slave上可看到新建的booker表:

        mysql> SHOW TABLES;
        +-----------------+
        | Tables_in_newdb |
        +-----------------+
        | booker          |
        | newtable        |
        +-----------------+
        2 rows in set (0.00 sec)

    但是在Master上却看不到,导致主、从上的newdb出现不一致:

        mysql> USE newdb;
        Reading table information for completion of table and column names
        You can turn off this feature to get a quicker startup with -A
        Database changed
        mysql> SHOW TABLES;                      //看不到Slave上新建的表
        +-----------------+
        | Tables_in_newdb |
        +-----------------+
        | newtable        |
        +-----------------+
        1 row in set (0.00 sec)

    完成上述验证后,在Slave上删除booker表,确保双方一致:

        mysql> DROP TABLE booker;
        Query OK, 0 rows affected (0.27 sec)

    3)修改/etc/my.cnf文件,重载配置

        [root@dbsvr2 ~]# vim /etc/my.cnf
        [mysqld]
        .. ..
        read_only=1                                      //启动只读模式
        [root@dbsvr2 ~]# systemctl restart mysqld.service          //重启服务

    4)再次在Slave上验证数据库写入操作

    仍然是以rwuser登入(不要用root哦)来验证,当尝试创建新表时会被拒绝:

        mysql> USE newdb;                                      //切换到newdb库
        Reading table information for completion of table and column names
        You can turn off this feature to get a quicker startup with -A
        Database changed
        mysql> CREATE TABLE booker(id int(12));     //新建表的写入操作失败
        ERROR 1290 (HY000): The MySQL server is running with the --read-only option so it cannot execute this statement
        mysql> DROP TABLE mytable;                      //删除表的写入操作一样会失败
        ERROR 1290 (HY000): The MySQL server is running with the --read-only option so it cannot execute this statement

    附加:

    一、设置binlog日志,修改配置文件后,启动mysqld服务报错,排错思路

      1> 检查SELinux是否设置为Permissing,如果没有就改为Permissing,可以直接设置setenforce 0【临时Permissive】,也可以修改/etc/selinux/config配置文件,设置selinux永久Permissive

      2> 检查/etc/my.cnf配置文件里binlog日志文件log_bin=/tmp/logdir/plj的修改路径/tmp/logdir/plj有没有创建

      3> 创建了路径目录/tmp/logdir/plj后,需要chown mysql /tmp/logdir  将文件目录归属给mysql用户,注意:备份的日志文件都在/tmp/logdir/下面,而不是/tmp/logdir/plj下面

      4> 检查httpd服务是否开启,有授权给网段用户可以登录的话,必须启动httpd才能正常启动mysqld

    二、mysql数据备份恢复,启动mysqld服务报错,排错思路

      1> mysql在设置备份服务后,备份完成后,重启mysqld服务失败,检查/var/lib/mysql目录是否归档为mysql用户和mysql组。

    全备份和增量备份思路:

    备份:
    # innobackupex --user=root --password=123456 /backup/mysql –no-timestamp     //全备份
    # innobackupex  --user=root --password=123456 --incremental /incr01 --incremental-basedir=/backup/mysql --no-timestamp    //增量备份
    # du -sh /backup/ /incr01/     //查看全备份和增量备份的文件大小

    恢复:
    # innobackupex  --user=root --password=123456 --apply-log  --redo-only /backup/mysql    //全备份的恢复
    # innobackupex  --user=root --password=123456 --apply-log  --redo-only /backup/mysql  --incremental-dir=/incr01    //增量备份的恢复

    模拟数据库误删除操作:
    # systemctl  stop  mysqld    
    # rm -rf /var/lib/mysql

    重建数据库目录并归档:
    # mkdir /var/lib/mysql     //重建/var/lib/mysql数据库目录,这步骤可以不要,下面innobackupex会自动创建
    # chown -R mysql:mysql /var/lib/mysql    //保证mysql用户对此目录的权限,上面若没有创建目录,这步骤可以放到下面

    # innobackupex --user=root --password=123456 --copy-back  /backup/mysql     //将backup/mysql里面的数据恢复回来
    # chown -R mysql:mysql /var/lib/mysql    //保证mysql用户对此目录的权限,上面若有这步骤可省略
    # systemctl  start mysqld.service   //重启数据库服务,登录验证

      附加:

    摘自:

    Linux公社       http://www.linuxidc.com/Linux/2014-02/96945.htm

    MySQL主从同步故障-Slave_SQL_Running: No

    故障现象:
    进入slave服务器,运行:
    mysql> show slave statusG
            .......
                Relay_Log_File: localhost-relay-bin.000535
                Relay_Log_Pos: 21795072
        Relay_Master_Log_File: localhost-bin.000094
    Slave_IO_Running: Yes
    Slave_SQL_Running: No
              Replicate_Do_DB:
          Replicate_Ignore_DB:
          ......
    解决办法一、
    Slave_SQL_Running: No
    1.程序可能在slave上进行了写操作
    2.也可能是slave机器重起后,事务回滚造成的.

    一般是事务回滚造成的:
    解决办法:
    mysql> slave stop;
    mysql> set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;
    mysql> slave start;
    解决办法二、
    首先停掉Slave服务:slave stop
    到主服务器上查看主机状态:
    记录File和Position对应的值
    进入master
    mysql> show master status;
    +----------------------+----------+--------------+------------------+
    | File                | Position | Binlog_Do_DB | Binlog_Ignore_DB |
    +----------------------+----------+--------------+------------------+
    | localhost-bin.000094 | 33622483 |              |                  |
    +----------------------+----------+--------------+------------------+
    1 row in set (0.00 sec)
    然后到slave服务器上执行手动同步:

    mysql> change master to
    > master_host='master_ip',
    > master_user='user',
    > master_password='pwd',
    > master_port=3306,
    > master_log_file=localhost-bin.000094',
    > master_log_pos=33622483 ;
    1 row in set (0.00 sec)
    mysql> slave start;
    1 row in set (0.00 sec)
    mysql> show slave statusG
    *************************** 1. row ***************************
    ........
              Master_Log_File: localhost-bin.000094
          Read_Master_Log_Pos: 33768775
                Relay_Log_File: localhost-relay-bin.000537
                Relay_Log_Pos: 1094034
        Relay_Master_Log_File: localhost-bin.000094
              Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB:
    手动同步需要停止master的写操作!
    查看mysql主从配置的状态及修正 slave不启动问题
    1、查看master的状态
    show master status;  //Position不应该为0
    show processlist; 
    //state状态应该为Has sent all binlog to slave; waiting for binlog to be updated
    2、查看slave状态
    show slave status;
    //Slave_IO_Running 与 Slave_SQL_Running 状态都要为Yes
    show processlist;
    //应该有两行state值为:
    Has read all relay log; waiting for the slave I/O thread to update it
    Waiting for master to send event

    3、错误日志
    MySQL安装目录 /usr/local/mysql
    MySQL日志目录 /usr/local/mysql/data/  形如,Hostname.err

    4、Change master to
    如果从库的Slave未启动,Slave_IO_Running为NO。
    可能是主库是的master的信息有变化,
    查看主库show master status;
    记录下File,Position字段,假设为‘mysql-bin.000004’,98;
    在从库执行:

    mysql>stop slave;
    mysql>change master to master_log_file='mysql-bin.000004',master_log_pos=98;
    mysql>start slave;
     


    5、SET global sql_slave_skip_counter=n;
    如果从库的slave_sql_running为NO。
    Err文件中记录:
    Slave:Error "Duplicate entry '1' for key 1" on query.....
    可能是master未向slave同步成功,但slave中已经有了记录。造成的冲突可以在从库上执行
    set global sql_slave_skip_counter=n;
    跳过几步。再restart slave就可以了。

    6、同步错误处理
    发现mysql slave服务器经常因为一些特殊字符或者符号产生的更新语句报错,整个同步也会因此而卡在那,最初的办法只是手动去出错的机器执行下面三条SQL语句,跳过错误即可。

    mysql>slave stop;
    mysql>set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;
    mysql>slave start;

    PS:本人多次遇到从数据库的同步进程自动停掉的问题,有时简单通过slave stop,slave start即可解决。有时slave start启动后又会自动停掉,这时使用 change master重设主数据库信息的方式解决了问题。

    说明:
    Slave_IO_Running:连接到主库,并读取主库的日志到本地,生成本地日志文件
    Slave_SQL_Running:读取本地日志文件,并执行日志里的SQL命令。

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  • 原文地址:https://www.cnblogs.com/baichuanhuihai/p/8313018.html
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