The InnoDB engine for MySql is now the default engine and the preferred choice for most operations. The install script of Hotaru has been using the older MyISAM engine for some time now going back to when Hotaru CMS was first developed. From Version 1.7 all tables except the Posts and Comments tables will be set up initially with InnoDB instead of MyISAM. The Posts and Comments may still use MyISAM as they have full text searching requirements which are not available with InnoDB yet. Here is a quick overview of the benefits of InnoDB over MyISAM Key Advantages of InnoDB InnoDB is a high-reliability and high-performance storage engine for MySQL. Key advantages of InnoDB include: Its design follows the ACID model, with transactions featuring commit, rollback, and crash-recovery capabilities to protect user data. Row-level locking (without escalation to coarser granularity locks) and Oracle-style consistent reads increase multi-user concurrency and performance. InnoDB tables arrange your data on disk to optimize common queries based on primary keys. Each InnoDB table has a primary key index called the clustered index that organizes the data to minimize I/O for primary key lookups. To maintain data integrity, InnoDB also supports FOREIGN KEY referential-integrity constraints. You can freely mix InnoDB tables with tables from other MySQL storage engines, even within the same statement. For example, you can use a join operation to combine data from InnoDB and MEMORY tables in a single query. InnoDB has been designed for CPU efficiency and maximum performance when processing large data volumes. from http://dev.mysql.com/doc/refman/5.0/en/innodb-storage-engine.html I have also provided a database optimizer plugin which will change the individual tables on your older Hotaru CMS installations. You can press the button to convert for Posts and Comments as well, but those will not be changed due to the above full text search requirements. I would recommend all to install this plugin and change over the tables when you have time http://forums.hotarucms.org/resources/db-optimize.48/ No code changes are required to use the plugin or to convert the database tables. It should work with all older versions of Hotaru CMS as well.