mysqld-max, An Extended mysqld Server

mysqld-max is the MySQL server (mysqld) configured with the following configure options:

OptionComment
--with-server-suffix=-maxAdd a -max suffix to the mysqld version string
--with-innodbSupport for InnoDB tables (MySQL 3.23 only)
--with-bdbSupport for Berkeley DB (BDB) tables
CFLAGS=-DUSE_SYMDIRSymbolic link support for Windows

The --with-innodb option for enabling InnoDB support is needed only in MySQL 3.23. In MySQL 4 and up, InnoDB is included by default.

You can find the MySQL-Max binaries at http://www.mysql.com/downloads/mysql-max-4.0.html.

The MySQL binary distributions Windows include both the standard mysqld.exe binary and the mysqld-max.exe binary. http://www.mysql.com/downloads/mysql-4.0.html. See Windows installation.

Note that BerkeleyDB (BDB) is not available for all platforms, so some of the Max binaries may not include it.

The following table shows which storage engines our MySQL-Max binaries include:

SystemBDBInnoDB
Windows/NT YY
AIX 4.3 NY
HP-UX 11.0 NY
Linux-Alpha NY
Linux-Intel YY
Linux-IA-64 NY
Solaris-Intel NY
Solaris-SPARC YY
SCO OSR5 YY
UnixWare YY
Mac OS X NY

Note that as of MySQL 4, you do not need a MySQL-Max server to obtain InnoDB support, because InnoDB is included by default.

You can check which storage engines are supported by your server by issuing the following statement:

mysql> SHOW VARIABLES LIKE "have_%";
+------------------+----------+
| Variable_name    | Value    |
+------------------+----------+
| have_bdb         | NO       |
| have_crypt       | YES      |
| have_innodb      | YES      |
| have_isam        | YES      |
| have_raid        | NO       |
| have_symlink     | DISABLED |
| have_openssl     | NO       |
| have_query_cache | YES      |
+------------------+----------+

The values in the second column indicate the server's level of support for each feature.:

ValueMeaning
YESThe feature is supported and is active.
NOThe feature is not supported. This value means the server was compiled without support for the feature, so it cannot be activated at runtime.
DISABLEDThe feature is supported but has been disabled. This occurs either because the server was started with an option that disables the feature, or because not all options required to enable it were given. In the latter case, the hostname.err file should contain a reason indicating why the option is disabled.

One situation in which you might see DISABLED occurs with MySQL 3.23 when the InnoDB storage engine is compiled in. In MySQL 3.23, you must supply at least the innodb_data_file_path option at runtime to set up the InnoDB tablespace. Without the options, InnoDB disables itself. See InnoDB in MySQL 3.23.

You can specify configuration options for the BDB storage engine, too, but BDB will nott disable itself without them. See BDB start.

mysqld_safe automatically tries to start any mysqld binary with the -max suffix. This makes it very easy to test out another mysqld binary in an existing installation. Just run configure with the options you want and then install the new mysqld binary as mysqld-max in the same directory where your old mysqld binary is located. See mysqld_safe.

On Linux, the MySQL-Max RPM uses the above mentioned mysqld_safe feature. (It just installs the mysqld-max executable, so mysqld_safe automatically uses this executable when mysqld_safe is restarted.)

This behavior means that if you install a MySQL-Max distribution, then upgrade later to a non-Max version of MySQL, mysqld_safe will still attempt to run the old mysql_max server. If you perform such an upgrade, manually removed the old mysqld_max server to ensure that mysqld_safe runs the new mysqld server.