Questions and Answers
For detailed upgrade information, see Section 2.19.1, “Upgrading MySQL”. Do not skip a major version when upgrading, but rather complete the process in steps, upgrading from one major version to the next in each step. This may seem more complicated, but it will you save time and trouble—if you encounter problems during the upgrade, their origin will be easier to identify, either by you or—if you have a MySQL Enterprise subscription—by MySQL support.
Storage engine support has changed as follows:
ISAM tables was removed in
MySQL 5.0 and you should now use the
MyISAM storage engine in place of
ISAM. To convert a table
simply issue a statement such as this one:
MyISAM tables was also removed in MySQL
5.0. This was formerly used to allow large tables in file
systems that did not support file sizes greater than 2GB.
All modern file systems allow for larger tables; in
addition, there are now other solutions such as
MERGE tables and views.
VARCHAR column type now
retains trailing spaces in all storage engines.
MEMORY tables (formerly known as
HEAP tables) can also contain