How to use mysqlfrm to restore frm table structure

1. mysqlfrm installation

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Since mysqlfrm is part of the mysql-utilities tool, we can install mysql-utilities, download the corresponding source code package, and compile and install it.

shell> tar -xvzf mysql-utilities-1.6.4.tar.gz 
shell> cd mysql-utilities-1.6.4
shell> python ./setup.py build
shell> python ./setup.py install

After the installation is completed, mysqlfrm and other executable files will be available in the corresponding python execution directory.

2. Introduction to mysqlfrm related parameters

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--basedir ：如 --basedir=/usr/local/percona-5.6.21
--server ： 如 --server=user:password@192.168.1.100:3306
--diagnostic ： 开启按字节模式来恢复frm结构
--user :启动MySQL用户，通过为mysql

3. Mysqlfrm uses

---------------------- ---

Use --basedir mode to restore:

[ 16:35:29-root@br3cy1sw:~ ]# mysqlfrm --basedir=/usr/local/percona-5.6.21/ /root/t1.frm --port=3434 --user=mysql --diagnostic
# WARNING The --port option is not used in the --diagnostic mode.
# WARNING: The --user option is only used for the default mode.
# WARNING: Cannot generate character set or collation names without the --server option.
# CAUTION: The diagnostic mode is a best-effort parse of the .frm file. As such, it may not identify all of the components of the table correctly. This is especially true for damaged files. It will also not read the default values for the columns and the resulting statement may not be syntactically correct.
# Reading .frm file for /root/t1.frm:
# The .frm file is a TABLE.
# CREATE TABLE Statement:
CREATE TABLE `root`.`t1` (
`a` int(11) NOT NULL,
`b` int(11) DEFAULT NULL,
`c` int(11) DEFAULT NULL,
`d` varchar(600) DEFAULT NULL,
PRIMARY KEY `PRIMARY` (`a`),
KEY `idx_t1_bc` (`b`,`c`)
) ENGINE=InnoDB;
    #...done.

Use --server mode to restore:

[ 16:35:10-root@br3cy1sw:~ ]#mysqlfrm --server=user:password@192.168.1.100:3306 /root/t1.frm --port=3434 --user=mysql --diagnostic
WARNING: Using a password on the command line interface can be insecure.
# WARNING The --port option is not used in the --diagnostic mode.
# WARNING: The --user option is only used for the default mode.
# Source on 192.168.1.100: ... connected.
# CAUTION: The diagnostic mode is a best-effort parse of the .frm file. As such, it may not identify all of the components of the table correctly. This is especially true for damaged files. It will also not read the default values for the columns and the resulting statement may not be syntactically correct.
# Reading .frm file for /root/t1.frm:
# The .frm file is a TABLE.
# CREATE TABLE Statement:
CREATE TABLE `root`.`t1` ( `a` int(11) NOT NULL, `b` int(11) DEFAULT NULL, `c` int(11) DEFAULT NULL,
`d` varchar(200) COLLATE `utf8_general_ci` DEFAULT NULL,
PRIMARY KEY `PRIMARY` (`a`),
KEY `idx_t1_bc` (`b`,`c`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    #...done.

Did you notice that the varchar recovered using --basedir is 3 times that of --server mode? This should be caused by mysqlfrm being unable to perform character encoding verification when using basedir mode.

Looked at the --server file again: (focus on the red and bold text), suggestions: When the --server mode can be used, try to use --server while ensuring that the mysqld environment is provided Consistent with the original production environment.

--server=server
Connection information for a server. Use this option or --basedir for the default mode.
 
If provided with the diagnostic mode, the storage engine and character set information are validated against this server.

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