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  • mydumper

    【1】mydumper介绍

    (1.1)基本概念与优劣

    而你的MySQL版本应该更新到5.5版本以上,mydumper作为一个实用工具,能够良好支持多线程工作,可以并行的多线程的从表中读入数据并同时写到不同的文件里这使得它在处理速度方面快于传统的mysqldump。

    mysqldumper其特征之一是在处理过程中需要对列表加以锁定,如果我们需要在工作时段执行备份工作,那么会引起DML阻塞不过现在的MySQL一般都是主从结构,备份也大部分在从上进行,所以锁的问题可以不用考虑因此mydumper能更优秀快速的完成备份任务

    mydumper特性

    1.多线程备份

    2因为是多线程逻辑备份,备份后会生成多个备份文件

    3.备份时对MyISAM表施加FTWRL(FLUSH TABLES WITH READ LOCK),会阻塞DML语句

    4.保证备份数据的一致性

    5.支持文件压缩

    6.支持导出binlog

    7.支持多线程恢复

    8.支持以守护进程模式工作,定时快照和连续二进制日志

    9.支持将备份文件切块

    mydumper优点

    1.轻量级C语言写的

    2.执行速度比mysqldump快10倍

    3.事务性和非事务性表一致的快照(适用于0.22以上版本)

    4.快速的文件压缩

    5.支持导出binlog

    6.多线程恢复(适用于0.2.1以上版本)

    7.以守护进程的工作方式,定时快照和连续二进制日志(适用于0.5.0以上版本)

    8.开源(GNUGPLv3)

    mydumper缺点

      mydumper的多线程备份是基于表的,当只有一张表或99张是小表,张是超级大表,mydumper不如mysqldump,甚至更慢

    对于大表情况注意使用参数-r

    (1.2)备份机制原理

    对于MySQL官方提供的逻辑备份工具 mysqldump , mydumper最大的特点就是可以采用多线程并行备份,大大提高了数据导出的速度。

    这里对mydumper的工作原理做个分析,看一下mydumper如何巧妙的利用Innodb引擎提供的MVCC版本控制的功能,实现多线程并发获取一致性数据。

    这里一致性数据指的是在某个时间点,导出的数据与导出的Binlog文件信息相匹配,如果导出了多张表的数据,这些不同表之间的数据都是同一个时间点的数据。

    在mydumper进行备份的时候,由一个主线程以及多个备份线程完成。

    其主线程的流程是:

      连接数据库

    FLUSH TABLES WITH READ LOCK 将脏页刷新到磁盘并获得只读锁

    START TRANSACTION /!40108 WITH CONSISTENT SNAPSHOT / 开启事物并获取一致性快照

    SHOW MASTER STATUS 获得binlog信息

    创建子线程并连接数据库

    为子线程分配任务并push到队列中

    UNLOCK TABLES / FTWRL / 释放锁

    子线程的主要流程是:

      连接数据库

      SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE

      START TRANSACTION /!40108 WITH CONSISTENT SNAPSHOT /

    从队列中pop任务并执行

    (1.3)图解备份原理

      

    【2】mydumper 使用

    (2.1)下载安装

    源码安装:

    [root@mysql-150 ~]# yum -y  install glib2-devel mysql-devel zlib-devel pcre-devel zlib gcc-c++ gcc cmake
    [root@mysql-150 ~]# wget https://launchpad.net/mydumper/0.9/0.9.1/+download/mydumper-0.9.1.tar.gz
    [root@mysql-150 ~]# tar zxf mydumper-0.9.1.tar.gz
    [root@mysql-150 ~]# cd mydumper-0.9.1/
    [root@mysql-150 mydumper-0.9.1]# pwd
    /root/mydumper-0.9.1
    [root@mysql-150 mydumper-0.9.1]# cmake .
    [root@mysql-150 mydumper-0.9.1]# make
    [root@mysql-150 mydumper-0.9.1]# make install
    #安装完成后生成两个二进制文件mydumper和myloader位于/usr/local/bin目录下
    [root@mysql-150 bin]# ls /usr/local/bin/
    mydumper  myloader

    rpm安装:

    https://launchpad.net/mydumper
     
    [root@localhost ~]# ls
    anaconda-ks.cfg   mydumper-0.9.5-2.el7.x86_64.rpm
    [root@localhost ~]# rpm -ivh mydumper-0.9.5-2.el7.x86_64.rpm 
    Preparing...                          ################################# [100%]
    Updating / installing...
       1:mydumper-0.9.5-2                 ################################# [100%]
    [root@localhost ~]# which mydumper
    /usr/bin/mydumper
    [root@localhost ~]# which myloader
    /usr/bin/myloader

    (2.2)mydumper参数介绍

    -B, --database              要备份的数据库,不指定则备份所有库
    -T, --tables-list           需要备份的表,名字用逗号隔开
    -o, --outputdir             备份文件输出的目录
    -s, --statement-size        生成的insert语句的字节数,默认1000000
    -r, --rows                  将表按行分块时,指定的块行数,指定这个选项会关闭 --chunk-filesize
    -F, --chunk-filesize        将表按大小分块时,指定的块大小,单位是 MB
    -c, --compress              压缩输出文件
    -e, --build-empty-files     如果表数据是空,还是产生一个空文件(默认无数据则只有表结构文件)
    -x, --regex                 是同正则表达式匹配 'db.table'
    -i, --ignore-engines        忽略的存储引擎,用都厚分割
    -m, --no-schemas            不备份表结构
    -k, --no-locks              不使用临时共享只读锁,使用这个选项会造成数据不一致
    --less-locking              减少对InnoDB表的锁施加时间(这种模式的机制下文详解)
    -l, --long-query-guard      设定阻塞备份的长查询超时时间,单位是秒,默认是60秒(超时后默认mydumper将会退出)
    --kill-long-queries         杀掉长查询 (不退出)
    -b, --binlogs               导出binlog
    -D, --daemon                启用守护进程模式,守护进程模式以某个间隔不间断对数据库进行备份
    -I, --snapshot-interval     dump快照间隔时间,默认60s,需要在daemon模式下
    -L, --logfile               使用的日志文件名(mydumper所产生的日志), 默认使用标准输出
    --tz-utc                    跨时区是使用的选项,不解释了
    --skip-tz-utc               同上
    --use-savepoints            使用savepoints来减少采集metadata所造成的锁时间,需要 SUPER 权限
    --success-on-1146           Not increment error count and Warning instead of Critical in case of table doesn't exist
    -h, --host                  连接的主机名
    -u, --user                  备份所使用的用户
    -p, --password              密码
    -P, --port                  端口
    -S, --socket                使用socket通信时的socket文件
    -t, --threads               开启的备份线程数,默认是4
    -C, --compress-protocol     压缩与mysql通信的数据
    -V, --version               显示版本号
    -v, --verbose               输出信息模式, 0 = silent, 1 = errors, 2 = warnings, 3 = info, 默认为 2

    (2.3)myloader参数介绍

    -d, --directory                   备份文件的文件夹
    -q, --queries-per-transaction     每次事物执行的查询数量,默认是1000
    -o, --overwrite-tables            如果要恢复的表存在,则先drop掉该表,使用该参数,需要备份时候要备份表结构
    -B, --database                    需要还原的数据库
    -e, --enable-binlog               启用还原数据的二进制日志
    -h, --host                        主机
    -u, --user                        还原的用户
    -p, --password                    密码
    -P, --port                        端口
    -S, --socket                      socket文件
    -t, --threads                     还原所使用的线程数,默认是4
    -C, --compress-protocol           压缩协议
    -V, --version                     显示版本
    -v, --verbose                     输出模式, 0 = silent, 1 = errors, 2 = warnings, 3 = info, 默认为2

    【3】mydumper备份实践

    (3.1)mydumper备份

    如下信息所示:

      我备份test库的所有表,用了多线程,默认4线程

    [root@localhost /data/dba]$ mydumper -u root -p b123456 -B test  -o /data/dba/test/  --verbose=3
    ** Message: 17:41:08.385: Connected to a MySQL server
    ** Message: 17:41:08.387: Started dump at: 2021-10-08 17:41:08
    
    ** Message: 17:41:08.387: Written master status
    ** Message: 17:41:08.388: Thread 1 connected using MySQL connection ID 1618810
    ** Message: 17:41:08.389: Thread 2 connected using MySQL connection ID 1618811
    ** Message: 17:41:08.389: Thread 3 connected using MySQL connection ID 1618812
    ** Message: 17:41:08.390: Thread 4 connected using MySQL connection ID 1618813
    ** Message: 17:41:08.398: Thread 3 dumping data for `test`.`game_users`
    ** Message: 17:41:08.398: Thread 4 dumping data for `test`.`log_test2`
    ** Message: 17:41:08.398: Thread 2 dumping data for `test`.`agent_cost`
    ** Message: 17:41:08.398: Thread 1 dumping data for `test`.`t2`
    ** Message: 17:41:08.399: Thread 3 dumping data for `test`.`agent_cost_game_cnt`
    ** Message: 17:41:08.399: Thread 1 dumping data for `test`.`agent_money_stock_hourly`
    ** Message: 17:41:08.399: Empty table test.log_test2
    ** Message: 17:41:08.399: Thread 4 dumping data for `test`.`game_users2`
    ** Message: 17:41:08.399: Non-InnoDB dump complete, unlocking tables
    ** Message: 17:41:08.399: Thread 3 dumping data for `test`.`goinc_variables_manu`
    ** Message: 17:41:08.399: Thread 2 dumping data for `test`.`log`
    ** Message: 17:41:08.399: Empty table test.goinc_variables_manu
    ** Message: 17:41:08.400: Thread 3 dumping data for `test`.`log_test`
    ** Message: 17:41:08.400: Thread 1 dumping data for `test`.`log_reversecard`
    ** Message: 17:41:08.400: Thread 4 dumping data for `test`.`priv`
    ** Message: 17:41:08.400: Empty table test.log
    ** Message: 17:41:08.400: Empty table test.log_test
    ** Message: 17:41:08.400: Empty table test.log_reversecard
    ** Message: 17:41:08.400: Thread 2 dumping data for `test`.`q1`
    ** Message: 17:41:08.400: Thread 3 dumping data for `test`.`q2`
    ** Message: 17:41:08.400: Thread 4 dumping data for `test`.`round_bills`
    ** Message: 17:41:08.400: Thread 1 dumping data for `test`.`sbtest1`
    ** Message: 17:41:08.400: Thread 3 dumping data for `test`.`sbtest2`
    ** Message: 17:41:08.400: Thread 2 dumping data for `test`.`sbtest3`
    ** Message: 17:41:08.400: Thread 4 dumping data for `test`.`sbtest4`
    ** Message: 17:41:10.283: Thread 4 dumping data for `test`.`sbtest5`
    ** Message: 17:41:10.566: Thread 3 dumping data for `test`.`t1`
    ** Message: 17:41:10.566: Thread 3 dumping data for `test`.`tc`
    ** Message: 17:41:10.566: Empty table test.tc
    ** Message: 17:41:10.567: Thread 3 dumping data for `test`.`tea_house_bills`
    ** Message: 17:41:10.567: Thread 3 dumping data for `test`.`tea_house_bills_bak`
    ** Message: 17:41:10.567: Empty table test.tea_house_bills_bak
    ** Message: 17:41:10.567: Thread 3 dumping data for `test`.`tea_prop_rich_log`
    ** Message: 17:41:10.568: Thread 3 dumping data for `test`.`test1`
    ** Message: 17:41:10.568: Thread 3 dumping data for `test`.`test111`
    ** Message: 17:41:10.568: Thread 3 dumping data for `test`.`test2`
    ** Message: 17:41:10.568: Empty table test.test2
    ** Message: 17:41:10.568: Thread 3 dumping data for `test`.`test20210820`
    ** Message: 17:41:10.568: Thread 3 dumping data for `test`.`test3`
    ** Message: 17:41:10.569: Empty table test.test3
    ** Message: 17:41:10.569: Thread 3 dumping data for `test`.`tmp1`
    ** Message: 17:41:10.569: Thread 3 dumping data for `test`.`tmp2`
    ** Message: 17:41:10.569: Thread 3 dumping schema for `test`.`agent_cost`
    ** Message: 17:41:10.569: Thread 3 dumping schema for `test`.`agent_cost_game_cnt`
    ** Message: 17:41:10.570: Thread 3 dumping schema for `test`.`agent_money_stock_hourly`
    ** Message: 17:41:10.570: Thread 3 dumping schema for `test`.`game_users`
    ** Message: 17:41:10.570: Thread 3 dumping schema for `test`.`game_users2`
    ** Message: 17:41:10.571: Thread 3 dumping schema for `test`.`goinc_variables_manu`
    ** Message: 17:41:10.571: Thread 3 dumping schema for `test`.`log`
    ** Message: 17:41:10.670: Thread 3 dumping schema for `test`.`log_reversecard`
    ** Message: 17:41:10.671: Thread 3 dumping schema for `test`.`log_test`
    ** Message: 17:41:10.671: Thread 3 dumping schema for `test`.`log_test2`
    ** Message: 17:41:10.671: Thread 3 dumping schema for `test`.`priv`
    ** Message: 17:41:10.671: Thread 3 dumping schema for `test`.`q1`
    ** Message: 17:41:10.671: Thread 3 dumping schema for `test`.`q2`
    ** Message: 17:41:10.672: Thread 3 dumping schema for `test`.`round_bills`
    ** Message: 17:41:10.672: Thread 3 dumping schema for `test`.`sbtest1`
    ** Message: 17:41:10.672: Thread 3 dumping schema for `test`.`sbtest2`
    ** Message: 17:41:10.672: Thread 3 dumping schema for `test`.`sbtest3`
    ** Message: 17:41:10.672: Thread 3 dumping schema for `test`.`sbtest4`
    ** Message: 17:41:10.673: Thread 3 dumping schema for `test`.`sbtest5`
    ** Message: 17:41:10.673: Thread 3 dumping schema for `test`.`t1`
    ** Message: 17:41:10.673: Thread 3 dumping schema for `test`.`t2`
    ** Message: 17:41:10.673: Thread 3 dumping schema for `test`.`tc`
    ** Message: 17:41:10.673: Thread 3 dumping schema for `test`.`tea_house_bills`
    ** Message: 17:41:10.673: Thread 3 dumping schema for `test`.`tea_house_bills_bak`
    ** Message: 17:41:10.674: Thread 3 dumping schema for `test`.`tea_prop_rich_log`
    ** Message: 17:41:10.674: Thread 3 dumping schema for `test`.`test1`
    ** Message: 17:41:10.674: Thread 3 dumping schema for `test`.`test111`
    ** Message: 17:41:10.674: Thread 3 dumping schema for `test`.`test2`
    ** Message: 17:41:10.674: Thread 3 dumping schema for `test`.`test20210820`
    ** Message: 17:41:10.675: Thread 3 dumping schema for `test`.`test3`
    ** Message: 17:41:10.675: Thread 3 dumping schema for `test`.`tmp1`
    ** Message: 17:41:10.675: Thread 3 dumping schema for `test`.`tmp2`
    ** Message: 17:41:10.675: Thread 3 dumping view for `test`.`users2`
    ** Message: 17:41:10.676: Thread 3 dumping view for `test`.`users3`
    ** Message: 17:41:10.676: Thread 3 dumping view for `test`.`users4`
    ** Message: 17:41:10.677: Thread 3 dumping view for `test`.`users5`
    ** Message: 17:41:10.730: Thread 2 dumping view for `test`.`v_a1`
    ** Message: 17:41:10.751: Thread 3 dumping view for `test`.`v_a2`
    ** Message: 17:41:10.752: Thread 3 shutting down
    ** Message: 17:41:10.754: Thread 1 shutting down
    ** Message: 17:41:10.787: Thread 2 shutting down
    ** Message: 17:41:11.333: Thread 4 shutting down
    ** Message: 17:41:11.333: Finished dump at: 2021-10-08 17:41:11

    与 mysqlpump 比较

    [root@localhost /data/dba/test]$ time mysqlpump --default-character-set=utf8mb4 --set-gtid-purged=ON --host=localhost  -B test default-parallelism=4>/data/dba/test_mysqlpump.sql
    mysqlpump: [WARNING] (1429) Unable to connect to foreign data source: Access denied for user 'leoaprd'@'10.20.53.12' (using password: 
    mysqlpump: [WARNING] (1429) Unable to connect to foreign data source: Access denied for user 'leoaprd'@'10.20.53.12' (using password: 
    Dump progress: 1/3 tables, 0/300 rows
    Dump progress: 14/32 tables, 833250/4932647 rows
    Dump progress: 14/32 tables, 1721000/4932647 rows
    Dump progress: 16/32 tables, 2625500/4932647 rows
    Dump progress: 16/32 tables, 3438750/4932647 rows
    Dump progress: 31/32 tables, 4152750/4932647 rows
    Dump progress: 31/32 tables, 4591000/4932647 rows
    Dump completed in 7672 milliseconds

    比它都快了一倍,yyds啊!

    (3.2)mydumper 备份出来的文件

      

    metadata:里面放的是 show master status

    *-schema.sql:里面放的是创建语句,表结构、视图结构、存储过程、函数等

    *表名.sql:直接就是 Insert into 语句

    (3.3)mydumper 实践相关语句参考

    1.备份单库:
    mydumper -u root -p 123456 --database db1 --outputdir db1
    mydumper -u root -p 123456 --database db1 --outputdir db1 --verbose=3
    备份所生成的文件:
    1.所有的备份文件在一个目录中,目录可以自己指定。
    2.目录中包含一个metadata文件
     记录了备份数据库在备份时间点的二进制日志文件名,日志的写入位置,
     如果是在从库进行备份,还会记录备份时同步至主库的二进制日志文件及写入位置
    3.每个表有两个备份文件:
      db1-schema-create.sql 数据库结构文件
     db1.tbs1-schema.sql 表结构文件
     db1.tbs1.sql 表数据文件
     如果对表文件分片,将生成多个备份数据文件,可以指定行数或指定大小分片
     
     
     
    2.备份多个数据库
    一次备份一个数据库,指定--database,使用--regex,正则表达式
    mydumper -u root -p 123456 --regex '^(db1.|db2.)' --outputdir db12 --verbose=3
    默认包含视图,但是routine,event,trigger需要另外指定参数。
     
    3.备份所有数据库:
    全库备份期间除了information_schema与performance_schema之外的库都会被备份
    mydumper -u root -p 123456 --outputdir fxfull --verbose=3
     
    4.备份单表
    mydumper -u root -p 123456 --database db1 --tables-list tbs,tbs2 --outputdir tbs12 --verbose=3
    多表用逗号分隔
    mydumper -u root -p 123456 --database db1 --tables-list tbs,tbs2,tbs3 --build-empty-files --outputdir tbs123 --verbose=3
     
     
    5.只备份结构
    mydumper -u root -p 123456 --database db1 --no-data --outputdir db1 --verbose=3
     
    6.开启压缩
    mydumper -u root -p 123456 --database db1 --compress --outputdir db1 --verbose=3
     
    7.导出触发器,存储过程,函数,事件,视图
      -G, --triggers  导出触发器
      -E, --events    导出事件
      -R, --routines  导出存储过程和函数
    创建存储过程:
    CREATE PROCEDURE proc()
    BEGIN
      SELECT * FROM tbs1;
    END;
     
    创建视图:
    create view v_tbs1 as select * from tbs;
     
    默认会导出视图,不会导出存储过程、函数、事件、触发器。
    -W, --no-views  不导视图
    mydumper -u root -p 123456 --database db1 --triggers -E --events --routines --outputdir tbs
     
    一致性备份:
    --less-locking 少锁等待时间
    mydumper -u root -p 123456 --database db1 --less-locking --outputdir tbs --verbose=3

    【4】myloader恢复实践

    (4.1)恢复到其他库

    可以在my.cnf中配置账户密码;

    [root@localhost /data/dba]$ myloader  -u root -p 123456 -B test2 -d /data/dba/test -v 3
    ** Message: 18:29:01.896: 4 threads created
    ** (myloader:9805): CRITICAL **: 18:26:30.919: Error restoring test1.agent_cost from file test.agent_cost-schema.sql.gz: Table 'agent_cost' already exists
    ** (myloader:9805): CRITICAL **: 18:26:30.920: Error restoring test1.agent_cost_game_cnt from file test.agent_cost_game_cnt-schema.sql.gz: Table 'agent_cost_game_cnt' already exists
    ** (myloader:9805): CRITICAL **: 18:26:30.922: Error restoring test1.agent_money_stock_hourly from file test.agent_money_stock_hourly-schema.sql.gz: Table 'agent_money_stock_hourly' already exists
    ** (myloader:9805): CRITICAL **: 18:26:30.950: Error restoring test1.round_bills from file test.round_bills-schema.sql.gz: Table 'round_bills' already exists
    ** (myloader:9805): CRITICAL **: 18:26:30.967: Error restoring test1.tea_house_bills from file test.tea_house_bills-schema.sql.gz: Table 'tea_house_bills' already exists
    ** (myloader:9805): CRITICAL **: 18:26:30.984: Error restoring test1.tea_prop_rich_log from file test.tea_prop_rich_log-schema.sql.gz: Table 'tea_prop_rich_log' already exists
    ** (myloader:9805): CRITICAL **: 18:26:31.003: Error restoring test1.agent_money_stock_hourly from file test.agent_money_stock_hourly.sql.gz: Duplicate entry '181476668-2021-03-17' for key 'PRIMARY'
    ** (myloader:9805): CRITICAL **: 18:26:31.003: Error restoring test1.agent_cost from file test.agent_cost.sql.gz: Duplicate entry '279719481-2021-03-17 03:00:00' for key 'PRIMARY'
    ** (myloader:9805): CRITICAL **: 18:26:31.005: Error restoring test1.round_bills from file test.round_bills.sql.gz: Duplicate entry '6080406-2021-03-17 03:42:39' for key 'PRIMARY'
    ** Message: 18:29:01.896: Creating table `test2`.`agent_cost`
    ** Message: 18:29:01.961: Creating table `test2`.`agent_cost_game_cnt`
    ** Message: 18:29:02.005: Creating table `test2`.`agent_money_stock_hourly`
    ** Message: 18:29:02.034: Creating table `test2`.`game_users`
    ** Message: 18:29:02.035: Creating table `test2`.`game_users2`
    ** Message: 18:29:02.041: Creating table `test2`.`goinc_variables_manu`
    ** Message: 18:29:02.043: Creating table `test2`.`log`
    ** Message: 18:29:02.051: Creating table `test2`.`log_reversecard`
    ** Message: 18:29:02.055: Creating table `test2`.`log_test`
    ** Message: 18:29:02.057: Creating table `test2`.`log_test2`
    ** Message: 18:29:02.058: Creating table `test2`.`priv`
    ** Message: 18:29:02.061: Creating table `test2`.`q1`
    ** Message: 18:29:02.063: Creating table `test2`.`q2`
    ** Message: 18:29:02.066: Creating table `test2`.`round_bills`
    ** Message: 18:29:02.095: Creating table `test2`.`sbtest1`
    ** Message: 18:29:02.098: Creating table `test2`.`sbtest2`
    ** Message: 18:29:02.100: Creating table `test2`.`sbtest3`
    ** Message: 18:29:02.103: Creating table `test2`.`sbtest4`
    ** Message: 18:29:02.106: Creating table `test2`.`sbtest5`
    ** Message: 18:29:02.109: Creating table `test2`.`t1`
    ** Message: 18:29:02.112: Creating table `test2`.`t2`
    ** Message: 18:29:02.113: Creating table `test2`.`tc`
    ** Message: 18:29:02.116: Creating table `test2`.`tea_house_bills`
    ** Message: 18:29:02.138: Creating table `test2`.`tea_house_bills_bak`
    ** Message: 18:29:02.154: Creating table `test2`.`tea_prop_rich_log`
    ** Message: 18:29:02.192: Creating table `test2`.`test1`
    ** Message: 18:29:02.195: Creating table `test2`.`test111`
    ** Message: 18:29:02.197: Creating table `test2`.`test2`
    ** Message: 18:29:02.199: Creating table `test2`.`test20210820`
    ** Message: 18:29:02.202: Creating table `test2`.`test3`
    ** Message: 18:29:02.204: Creating table `test2`.`tmp1`
    ** Message: 18:29:02.206: Creating table `test2`.`tmp2`
    ** Message: 18:29:02.209: Creating table `test2`.`users2`
    ** Message: 18:29:02.209: Creating table `test2`.`users3`
    ** Message: 18:29:02.210: Creating table `test2`.`users4`
    ** Message: 18:29:02.211: Creating table `test2`.`users5`
    ** Message: 18:29:02.211: Creating table `test2`.`v_a1`
    ** Message: 18:29:02.212: Creating table `test2`.`v_a2`
    ** Message: 18:29:02.213: Thread 1 restoring `test`.`game_users` part 0
    ** Message: 18:29:02.213: Thread 2 restoring `test`.`t2` part 0
    ** Message: 18:29:02.213: Thread 3 restoring `test`.`agent_cost` part 0
    ** Message: 18:29:02.213: Thread 4 restoring `test`.`agent_cost_game_cnt` part 0
    ** Message: 18:29:02.213: Thread 1 restoring `test`.`agent_money_stock_hourly` part 0
    ** Message: 18:29:02.213: Thread 2 restoring `test`.`game_users2` part 0
    ** Message: 18:29:02.214: Thread 2 restoring `test`.`priv` part 0
    ** Message: 18:29:02.215: Thread 2 restoring `test`.`q1` part 0
    ** Message: 18:29:02.216: Thread 2 restoring `test`.`q2` part 0
    ** Message: 18:29:02.217: Thread 2 restoring `test`.`round_bills` part 0
    ** Message: 18:29:02.219: Thread 1 restoring `test`.`sbtest1` part 0
    ** Message: 18:29:02.220: Thread 4 restoring `test`.`sbtest2` part 0
    ** Message: 18:29:02.222: Thread 3 restoring `test`.`sbtest3` part 0
    ** Message: 18:29:02.222: Thread 2 restoring `test`.`sbtest4` part 0
    ** Message: 18:29:23.049: Thread 3 restoring `test`.`sbtest5` part 0
    ** Message: 18:29:24.115: Thread 1 restoring `test`.`t1` part 0
    ** Message: 18:29:24.116: Thread 1 restoring `test`.`tea_house_bills` part 0
    ** Message: 18:29:24.126: Thread 1 restoring `test`.`tea_prop_rich_log` part 0
    ** Message: 18:29:24.130: Thread 1 restoring `test`.`test1` part 0
    ** Message: 18:29:24.131: Thread 1 restoring `test`.`test111` part 0
    ** Message: 18:29:24.131: Thread 1 restoring `test`.`test20210820` part 0
    ** Message: 18:29:24.132: Thread 1 restoring `test`.`tmp1` part 0
    ** Message: 18:29:24.132: Thread 1 restoring `test`.`tmp2` part 0
    ** Message: 18:29:24.133: Thread 1 shutting down
    ** Message: 18:29:24.160: Thread 2 shutting down
    ** Message: 18:29:24.220: Thread 4 shutting down
    ** Message: 18:29:36.068: Thread 3 shutting down
    ** Message: 18:29:36.068: Creating table `test2`.`users2`
    ** Message: 18:29:36.070: Creating table `test2`.`users3`
    ** Message: 18:29:36.072: Creating table `test2`.`users4`
    ** Message: 18:29:36.073: Creating table `test2`.`users5`
    ** Message: 18:29:36.074: Creating table `test2`.`v_a1`
    ** Message: 18:29:36.075: Creating table `test2`.`v_a2`

    那我们发现,其实是没有 drop table if exists 的,在建表语句中;

    同理,还会有主键重复等情况;

    其他的多线程恢复,是OK的!我访问你的是压缩的文件,也是可以的

      

     命令不用改变,myloader 会自动识别;

    【5】开general log 查看 mydumper究竟是如何运行的

    (5.1)单库备份图解

    # mydumper备份
    [root@mysql-150 mysql]# mydumper -u root -p 123456  -P 3306 -h 127.0.0.1 -B beta  -o /data/backup/mysql/

     主要是这些步骤

       

       

     UNLOCK TABLES后截图没截图玩,最后有5个quit 信息

    上面两个截图是完整的备份步骤

    (5.2) 单个库备份过程(这个库是的引擎是 innodb) 

    这里我总结一下

    1. 第一个发起备份的tcp信息
    FLUSH TABLES WITH READ LOCK  # 加全局锁,防止写入
    START TRANSACTION /*!40108 WITH CONSISTENT SNAPSHOT */ # 开启事务
    /*!40101 SET NAMES binary*/  # 获取当前数据库的状态信息,就是数据库当前正在使用的二进制日志及当前执行二进制日志位置,执行了哪些GTID
    SHOW MASTER STATUS
    SHOW SLAVE STATUS
     
    2. 剩下的4个tcp 信息内容基本是同时工作的(也就是多线程),内容都是
    SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ  #把当前会话事务隔离级别改为可重复读
    START TRANSACTION /*!40108 WITH CONSISTENT SNAPSHOT */ # 开启事务
     
    3. 获取相应的库信息,表信息,数据信息
    Init DB   beta
    SHOW TABLE STATUS
    SHOW CREATE DATABASE `beta`
    SELECT /*!40001 SQL_NO_CACHE */ * FROM `beta`.`t1`
    SELECT /*!40001 SQL_NO_CACHE */ * FROM `beta`.`t2`
    SHOW CREATE TABLE `beta`.`t1`
    SHOW CREATE TABLE `beta`.`t2`
     
    4. 解锁
    UNLOCK TABLES /* FTWRL */
     
    5. 最后备份结束,退出事务

    注:由于我的库很小,所以一下就结束了。

    (5.3)总结备份原理

    1、主线程 FLUSH TABLES WITH READ LOCK, 施加全局只读锁,保证数据的一致性 

    2、读取当前时间点的二进制日志文件名和日志写入的位置并记录在metadata文件中,以供即使点恢复使用 

    3、N个(线程数可以指定,默认是4)dump线程把事务隔离级别改为可重复读 并开启读一致的事物 

    4、dump non-InnoDB tables, 首先导出非事物引擎的表 

    5、主线程 UNLOCK TABLES 非事物引擎备份完后,释放全局只读锁 

    6、dump InnoDB tables, 基于事物导出InnoDB表 

    7、事物结束

    【6】mydumper的坑

    参考官网BUG报告:https://bugs.launchpad.net/mydumper

    【参考文档】

    https://www.cnblogs.com/keme/p/11679446.html

    https://blog.csdn.net/qq_34556414/article/details/106884371

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  • 原文地址:https://www.cnblogs.com/gered/p/15381240.html
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