MySQL Reference Manual :: D.3 Changes in release 4.0.x (Production)

The InnoDB storage engine is now included in the standard binaries, adding transactions, row-level locking, and foreign keys. See Chapter 15, The InnoDB Storage Engine.

A query cache, offering vastly increased performance for many applications. By caching complete result sets, later identical queries can return instantly. See Section 5.12, “The MySQL Query Cache”.

Improved full-text indexing with boolean mode, truncation, and phrase searching. See Section 12.7, “Full-Text Search Functions”.

Enhanced MERGE tables, now supporting INSERT statements and AUTO_INCREMENT. See Section 14.2, “The MERGE Storage Engine”.

UNION syntax in SELECT. See Section 13.2.7.2, “UNION Syntax”.

Multiple-table DELETE statements. See Section 13.2.1, “DELETE Syntax”.

libmysqld, the embedded server library. See Section 24.2.16, “libmysqld, the Embedded MySQL Server Library”.

Additional GRANT privilege options for even tighter control and security. See Section 13.5.1.3, “GRANT and REVOKE Syntax”.

Management of user resources in the GRANT system, particularly useful for ISPs and other hosting providers. See Section 5.7.4, “Limiting Account Resources”.

Dynamic server variables, allowing configuration changes to be made without having to stop and restart the server. See Section 13.5.3, “SET Syntax”.

Improved replication code and features. See Chapter 6, Replication in MySQL.

Numerous new functions and options.

Changes to existing code for enhanced performance and reliability.