mydumper是针对mysql数据库备份的一个轻量级第三方的开源工具，备份方式为逻辑备份。它支持多线程，备份速度远高于原生态的mysqldump以及众多优异特性。与其相配套的恢复工具则是myloader，主要用于将dump出来的sql以并行的方式进行恢复。本文主要描述myloader的使用方法并给出示例。
有关mydumper的相关参考
mydumper备份mysql数据库示例
mydumper安装及安装故障汇总
1、单库的备份与恢复
[root@app ~]# mydumper -u leshami -p xxx -B sakila -o /tmp/bak
[root@app ~]# mysql -urobin -pxxx -e "show databases"|grep restoredb
[root@app ~]# mysql -urobin -pxxx \
> -e "create table sakila.tb like sakila.actor; ###创建测试表
> insert into sakila.tb select * from sakila.actor"
###将备份库恢复到一个新数据库，如restoredb
[root@app ~]# myloader -u leshami -p xxx -B restoredb -d /tmp/bak
[root@app ~]# mysql -urobin -pxxx -e "show databases"|grep restoredb
restoredb
###恢复到原库
[root@app ~]# myloader -u leshami -p xxx -B sakila -d /tmp/bak
** (myloader:3642): CRITICAL **: Error restoring sakila.category from file sakila.category-schema.sql: Table 'category' already exists
---增加-o参数进行覆盖恢复
[root@app ~]# myloader -u leshami -p xxx -o -B sakila -d /tmp/bak
2、单表恢复
[root@app ~]# mysql -urobin -pxxx -e "drop table sakila.tb"
[root@app ~]# mysql -urobin -pxxx -e "select count(*) from sakila.tb"
Warning: Using a password on the command line interface can be insecure.
ERROR 1146 (42S02) at line 1: Table 'sakila.tb' doesn't exist
###直接调用备份的schema以及数据文件执行即可
[root@app ~]# mysql -urobin -pxxx \
> -e "use sakila;
> source /tmp/bak/sakila.tb-schema.sql
> source /tmp/bak/sakila.tb.sql"
###验证结果
[root@app ~]# mysql -urobin -pxxx -e "select count(*) from sakila.tb"
Warning: Using a password on the command line interface can be insecure.
+----------+
| count(*) |
+----------+
| 200 |
+----------+
3、实例级别的备份与恢复
[root@app ~]# rm -rf /tmp/bak/*
[root@app ~]# mydumper -u leshami -p xxx --regex '^(?!(mysql|test))' -o /tmp/bak
###尝试删除部分数据库
[root@app ~]# mysql -urobin -pxxx \
> -e "drop database tempdb;drop database sakila"
###基于全部备份文件进行恢复
[root@app ~]# myloader -u leshami -p xxx -o -d /tmp/bak
4、获取帮助
[root@app ~]# myloader --help
Usage:
myloader [OPTION...] multi-threaded MySQL loader
Help Options:
-?, --help Show help options
Application Options:
-d, --directory Directory of the dump to import
-q, --queries-per-transaction Number of queries per transaction, default 1000
还原期间每个事务insert的数目，缺省是1k
-o, --overwrite-tables Drop tables if they already exist(表存在即覆盖)
-B, --database An alternative database to restore into
-e, --enable-binlog Enable binary logging of the restore data
-h, --host The host to connect to
-u, --user Username with privileges to run the dump
-p, --password User password
-P, --port TCP/IP port to connect to
-S, --socket UNIX domain socket file to use for connection
-t, --threads Number of threads to use, default 4
-C, --compress-protocol Use compression on the MySQL connection
-V, --version Show the program version and exit
-v, --verbose Verbosity of output, 0 = silent, 1 = errors, 2 = warnings, 3 = info, default 2