mydumper是针对mysql数据库备份的一个轻量级第三方的开源工具，备份方式术语逻辑备份。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。因此该工具是DBA们的不二选择。本文主要描述该工具的安装及其出现异常的解决方法。
1、mydumper特性(直接参考readme)
* Parallelism (hence, speed) and performance (avoids expensive character set conversion routines, efficient code overall)
* Easier to manage output (separate files for tables, dump metadata, etc, easy to view/parse data)
* Consistency - maintains snapshot across all threads, provides accurate master and slave log positions, etc
* Manageability - supports PCRE for specifying database and tables inclusions and exclusions
It does not support schema dumping and leaves that to 'mysqldump --no-data'
2、获取mydumper及安装方法
下载地址：https://launchpad.net/mydumper
== How to build it? ==
Run:
cmake .
make
One needs to install development versions of required libaries (MySQL, GLib, ZLib, PCRE):
NOTE: you must use the correspondent mysql devel package.
* Ubuntu or Debian: apt-get install libglib2.0-dev libmysqlclient15-dev zlib1g-dev libpcre3-dev libssl-dev
* Fedora, RedHat and CentOS: yum install glib2-devel mysql-devel zlib-devel pcre-devel openssl-devel
* openSUSE: zypper install glib2-devel libmysqlclient-devel pcre-devel zlib-devel
* MacOSX: port install glib2 mysql5 pcre pkgconfig cmake
(You may want to run 'port select mysql mysql5' afterwards)
One has to make sure, that pkg-config, mysql_config, pcre-config are all in $PATH
Binlog dump is disabled by default to compile with it you need to add -DWITH_BINLOG=ON to cmake options
###如果要使用binlog dump在编译的时候需要使用-DWITH_BINLOG=ON
3、快照工作原理
== How does consistent snapshot work? ==
This is all done following best MySQL practices and traditions:
* As a precaution, slow running queries on the server either abort the dump, or get killed
* Global write lock is acquired ("FLUSH TABLES WITH READ LOCK")
* Various metadata is read ("SHOW SLAVE STATUS","SHOW MASTER STATUS")
* Other threads connect and establish snapshots ("START TRANSACTION WITH CONSISTENT SNAPSHOT")
** On pre-4.1.8 it creates dummy InnoDB table, and reads from it.
* Once all worker threads announce the snapshot establishment, master executes "UNLOCK TABLES" and starts queueing jobs.
This for now does not provide consistent snapshots for non-transactional engines - support for that is expected in 0.2 :)
4、如何过滤数据库
== How to exclude (or include) databases? ==
Once can use --regex functionality, for example not to dump mysql and test databases:
mydumper --regex '^(?!(mysql|test))'
Of course, regex functionality can be used to describe pretty much any list of tables.
== How to exclude MERGE or Federated tables ==
Use same --regex exclusion syntax. Again, engine-specific behaviors are targetted for 0.2
5、实际安装过程
# ls mydump*
mydumper-0.6.2.tar.gz
# tar -xvf mydumper-0.6.2.tar.gz
# cd mydumper-0.6.2
[root@GZ-APP-BAK01 mydumper-0.6.2]# cmake .
[root@GZ-APP-BAK01 mydumper-0.6.2]# make && make install
6、安装过程中的异常
错误1：
CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the CMake files:
PCRE_INCLUDE_DIR (ADVANCED)
used as include directory in directory /root/mydumper-0.6.2
PCRE_PCRE_LIBRARY (ADVANCED)
linked by target "mydumper" in directory /root/mydumper-0.6.2
linked by target "myloader" in directory /root/mydumper-0.6.2
###需要安装pcre-devel包，yum install pcre-devel
错误2：
CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the CMake files:
MYSQL_INCLUDE_DIR (ADVANCED)
used as include directory in directory /home/robin/mydumper-0.6.2
used as include directory in directory /home/robin/mydumper-0.6.2
used as include directory in directory /home/robin/mydumper-0.6.2
###出现上述错误，是由于没有配置MYSQL_INCLUDE_DIR目录。
###如果是编译安装到非缺省路径，可以将mysql安装路径添加到/etc/profile或者家目录~/.bash_profile后source生效
错误3：
[root@GZ-APP-BAK01 ~]# mydumper --help|more
mydumper: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory
[root@GZ-APP-BAK01 ~]# mydumper
mydumper: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory
###出现上述错误，应考虑建立软链
# which libmysqlclient.so.18
/app/soft/mysql/lib/libmysqlclient.so.18
# ln -s /app/soft/mysql/lib/libmysqlclient.so.18 /usr/lib/libmysqlclient.so.18
错误4：
# mydumper -uusr1 -ppwd -B blos -o /tmp/bak
option parsing failed: Error parsing option -r, try --help
###参数和字符串不能连着写，笔者刚开始是也是丈二和尚摸不着头脑。
# mydumper --version
mydumper 0.6.2, built against MySQL 5.6.22
7、获取帮助
# mydumper --help|more
Usage:
mydumper [OPTION...] multi-threaded MySQL dumping
Help Options:
-?, --help Show help options
Application Options:
-B, --database Database to dump
-T, --tables-list Comma delimited table list to dump (does not exclude regex option)
-o, --outputdir Directory to output files to
-s, --statement-size Attempted size of INSERT statement in bytes, default 1000000
-r, --rows Try to split tables into chunks of this many rows. This option turns off --chunk-filesize
-F, --chunk-filesize Split tables into chunks of this output file size. This value is in MB
-c, --compress Compress output files
-e, --build-empty-files Build dump files even if no data available from table
-x, --regex Regular expression for 'db.table' matching
-i, --ignore-engines Comma delimited list of storage engines to ignore
-m, --no-schemas Do not dump table schemas with the data
-k, --no-locks Do not execute the temporary shared read lock. WARNING: This will cause inconsistent backups
--less-locking Minimize locking time on InnoDB tables.
-l, --long-query-guard Set long query timer in seconds, default 60
-K, --kill-long-queries Kill long running queries (instead of aborting)
-D, --daemon Enable daemon mode
-I, --snapshot-interval Interval between each dump snapshot (in minutes), requires --daemon, default 60
-L, --logfile Log file name to use, by default stdout is used
--tz-utc SET TIME_ZONE='+00:00' at top of dump to allow dumping of TIMESTAMP data when a server has
data in different time zones or data is being moved between servers with different time zones,
defaults to on use --skip-tz-utc to disable.
--skip-tz-utc
--use-savepoints Use savepoints to reduce metadata locking issues, needs SUPER privilege
--success-on-1146 Not increment error count and Warning instead of Critical in case of table doesn't exist
--lock-all-tables Use LOCK TABLE for all, instead of FTWRL
-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
