• zerofill( N ) 

The most significant N  bytes in the value are always 0 and are not stored. 

• no zeros 

Do not store zeros. 

• always zero 

Zero values are stored using one bit. 

• Huff tree 

The number of the Huffman tree associated with the column. 

• Bits 

The number of bits used in the Huffman tree. 

After you run myisampack , use myisamchk  to re-create any indexes. At this time, you can also sort the index blocks and create statistics needed for the MySQL optimizer to work more efficiently: 

myisamchk -rq --sort-index --analyze tbl_name .MYI 

After you have installed the packed table into the MySQL database directory, you should execute mysqladmin flush-tables  to force mysqld  to start using the new table. 

To unpack a packed table, use the --unpack  option to myisamchk . 

## 4.6.7 mysql_config_editor — MySQL Configuration Utility 

The mysql_config_editor  utility enables you to store authentication credentials in an obfuscated login path file named .mylogin.cnf . The file location is the %APPDATA%\MySQL  directory on Windows and the current user’s home directory on non-Windows systems. The file can be read later by MySQL client programs to obtain authentication credentials for connecting to MySQL Server. 

The unobfuscated format of the .mylogin.cnf  login path file consists of option groups, similar to other option files. Each option group in .mylogin.cnf  is called a “login path,”  which is a group that permits only certain options: host , user , password , port  and socket . Think of a login path option group as a set of options that specify which MySQL server to connect to and which account to authenticate as. Here is an unobfuscated example: 

[client] user = mydefaultname password = mydefaultpass host = 127.0.0.1 [mypath] user = myothername password = myotherpass host = localhost 

When you invoke a client program to connect to the server, the client uses .mylogin.cnf  in conjunction with other option files. Its precedence is higher than other option files, but less than options specified explicitly on the client command line. For information about the order in which option files are used, see Section 4.2.2.2, “Using Option Files” . 

