September 16, 2003 Table types in MySQL: Part 1 - HEAP tables By Ian Gilfillan The MySQL table types We all know accessing data in RAM is a lot quicker than accessing data on disk. So, with this in mind, wouldn't it make sense for MySQL to store as much data as possible in memory? The answer is of course yes, and MySQL can in a number of ways. Query caches, holding indexes in memory, and most extreme of all, holding an entire table in memory. The latter is the topic of this article. Tables in memory are called HEAP tables. The MySQL table types include: * MyISAM tables, the default table type, which employs table locking, making it ideal for high volume select, low volume insert/update environments, such as most websites. * InnoDB tables, which supports transactions and referential integrity * ISAM tables, the old MySQL table type, replaced by MyISAM in most instances now. * BDB, which are also transaction safe. * MERGE tables, a table type for a collection of M