About MySQL InnoDB

Starting with MySQL version 5.5 InnoDB is already the default table storage engine

InnoDB

1: Full acid support

2: Row-level lock support

3: Support MVCC

4: Support for foreign keys

MySQL Version 5.1

Prior to MySQL version 5.1, InnoDB was included in the MySQL binary release and updated with MySQL update

Version 5.1 MySQL allows developers to dynamically load the storage engine so that updates to the storage engine are not limited by the MySQL version.

This means that the MySQL5.1 version can support 2 InnoDB storage engines

1: Statically compiled InnoDB

2: Dynamically loaded InnoDB also known as: InnoDB Plugin

Because multiple rollback segments are not supported, the maximum number of things concurrency that InnoDB plugin supports is limited to 1023

MySQL 5.5 version corresponds to innodb1.1.* version

MySQL 5.6 Version corresponds to innodb1.2.* version

About MySQL InnoDB