MySQL 5.5是MySQL數(shù)據(jù)庫中的一個(gè)重要版本，它于2010年12月15日發(fā)布。此版本解決了上一個(gè)版本中的一些安全問題、漏洞和缺陷。此外，該版本對于性能和可擴(kuò)展性進(jìn)行了改進(jìn)。

RELEASE NOTES ENHANCEMENTS IN MYSQL 5.5
MySQL Enterprise Edition includes the most comprehensive set of advanced features and management tools for MySQL.
MySQL 5.5 includes several high availability solutions such as semi-synchronous replication and new heartbeat and distributed recovery mechanisms for MySQL Cluster. Further improvements in replication have also been made, such as support for row-based replication, and the ability to execute stored procedures on slaves.
The optimizer has been enhanced for better performance, and includes improvements to subqueries, derived tables, and views, among other areas.
The improved InnoDB storage engine provides higher scalability, availability and performance, with support for more flexible data compression and improved data organization on disk.
The Partitioning feature has been improved, including the addition of subpartitioning, the ability to merge partitions, and support for foreign keys and triggers.
For more information, see the MySQL 5.5 Release Notes.

總之，MySQL 5.5是MySQL數(shù)據(jù)庫的重要版本，它在安全、性能和可擴(kuò)展性方面都有所改進(jìn)，為MySQL數(shù)據(jù)庫用戶提供了更好的體驗(yàn)。