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MySQL Server functions

Which languages are supported by MySQL?

mysqld can give error messages in the following languages: Czech, Dutch, English (default), French, German, Norwegian, Norwegian-ny, Polish, Portuguese, Spanish and Swedish.

To start mysqld with a language use one of the --language=lang or -L lang switches:

mysqld --language=swedish or mysqld --language=/usr/local/share/swedish

Note that all the language names are in lowercase.

By default, the language files are located in `mysql_base_dir/share/LANGUAGE/'.

Character set used for data & sorting.

By default, MySQL will use the ISO8859-1 (Latin1) character set. This is the character set used in the USA and western Europe.

The character set decides what characters are allowed in names and how things are sorted by the ORDER BY and GROUP BY commands.

You may change this at compile time by the configure switch --with-charset=charset. See section Quick installation overview..

The Update log

When started with the --log-update=file_name switch mysqld makes a log file with all SQL command that update data. It results in a file with name of file_name.# where # is a number that is increased for each reload. If you do not give a file name the current hostname is used.

The logging is smart since it only writes statements that really update data. So an UPDATE or a DELETE with a WHERE that finds no rows is not written to the log. It even skips UPDATEs that update a column to the value it had before.

The current limitations of --log-update are:

TIMESTAMP and all other updates with time functions will get the current date instead of the orignal date.

LAST_INSERT_ID() values should be logged for more safety.

How big can MySQL tables be?

Currently a table is limited to the operation system file size. On Linux the current limit is 2G, on Solaris 2.5.1 the limit is 4G and on Solaris 2.6 the limit is going to be 1000G. To get more that 4G requires some changes to MySQL that are on the Todo. See section List of things we want to add to MySQL in the future..

If your big table is going to be read_only, you could use pack_isam (See section The MySQL compressed read only table generator) to merge and compress many tables to one. As pack_isam usually compresses a table by at least 50%, you can have much bigger tables.

Another solution can be the included MERGE library, which allows one to handle a collection of identical tables as one. Currently MERGE can only be used to scan a collection of tables because it doesn't support indexes. We will add indexes to this in the near future. Identical in this case means that all tables are created with identical column information.

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