There is a notion that MySql never was like a real Database since the last few versions. MySql did not support the foreign keys until recently when it was made possible through the InnoDB engine. InnoDB engine has been gaining popularity over the default MyIsam mainly because of its support for transactions. Current belief is that MyIsam is the fastest for read access and InnoDb is better only when the transactions are required. Also, if there are many modifications of the data, it is believed that InnoDB works faster because it uses row locking unlike MyIsam’s table locking. Although, the data updation finishes fast enough before another process can perform its operation. However, there is a lot of decision making involved in deciding which storage engine to use. Many a times it makes perfect sense to use different engines within a single application. The other factor that goes into consideration is the memory requirement as InnoDB loads the entire table into memory for processing. MyIsam loads only the MyIsam index into memory for processing table data which makes it better suited for server that do not have lot of memory allocated or that aren’t dedicated database servers.
