MySQL Information

Adjusting MySQL memory settings is the key to improving your databases performance. These settings are declared using directives in the my.ini file. We cover the most important settings on this site. MySQL performs 2 different types of memory allocations, global (shared by all connections and databases) or per-connection.
This is important to understand before you use large value. While 100MB might not be much for a global setting, it's a huge value for a per-connection setting.

Here is the simplified math:
min_memory_needed = global_buffers + (thread_buffers * max_connections)

Important Change in MySQL 4.1

*) Character Sets

With version 4.0, you certainly have a choice of character sets... but once you've made the choice, you have to stick with it. For example, with version 4.0 you can't say "this database has character set X (by default), but Table1.column1 will have character set Y while Table1.column2 will have character set Z." With version 4.1 you can.

Definitions:
character set: Set of symbols and encodings.
collation: Set of rules for comparing characters in a character set

The "Western European" character sets cover most West European languages and have latin1 as the default character set with latin1_swedish_ci as the default collation. This is the most common setting for MySQL users.

Optimize all databases.
1) This command will go through all your databases and optimize all your database tables for optimal performance;

mysqlcheck -o -u root -p --all-databases

The database format InnoDB is becoming more mature since Mysql 4.1.

However the MyISAM is faster for most applications. The main advantage of InnoDB is that it enable row locking versus table locking for MyISAM write.
If you applications performs many simultaneous writes to the same table InnoDB, it might be a better choice for that particular table. However most web site do not have this issue. Even on a busy forum site (for example: a vbulletin site) concurrent writes are pretty rare. If you start getting constant database errors when reading/wrinting to large table tables it might be time to upgrade that table to InnoDB.