Software update: InnoDB 3.23.43b

Heikki Tuuri of Innobase Oy has a new source release of InnoDB released, based on MySQL 3.23.43. New in InnoDB 3.23.43b is the long-awaited support for foreign key constraints. This makes InnoDB the first MySQL table type to be provided with foreign keys. Furthermore, this release has some minor improvements and bug fixes:

New release: InnoDB source version 3.23.43b released for download.

• As the first table type in MySQL it features foreign key constraints which help to guard the integrity of your data. An example:

  CREATE TABLE parent(id INT NOT NULL, PRIMARY KEY (id)) TYPE=INNODB;
  
  CREATE TABLE child(id INT, parent_id INT, INDEX par_ind (parent_id), FOREIGN KEY (parent_id) REFERENCES parent(id)) TYPE=INNODB;

  see the manual for more information.

• DROP DATABASE will now work also for InnoDB tables. Also innodb_monitor has been improved.
• Accent characters in the default character set latin1 are ordered according to the MySQL ordering. NOTE: if you are using latin1 and have inserted characters whose code is > 127 to an indexed CHAR column, you should run CHECK TABLE on your table when you upgrade to 3.23.43b or later, and drop and reimport the table if CHECK TABLE reports an error!
• InnoDB calculates better table cardinality estimates. The accuracy is now +-10 %.
• The error handling of a deadlock has changed. In .43 a deadlock rolls back only the SQL statement, in .43b it rolls back the whole transaction. A deadlock will no longer return table handler error 1000000, but a new MySQL error code indicating a deadlock. A lock wait timeout returns table handler error 1000001.
• Several bug fixes.