MySQL Community Edition is a freely downloadable version of the world's most popular open source database that is supported by an active community of open source developers and enthusiasts.
MySQL delivers enterprise features, including:
- Partitioning to improve performance and management of very large database environments
- Row-based/Hybrid Replication for improved replication security
- Event Scheduler to create and schedule jobs that perform various database tasks
- XPath Support
- Dynamic General/Slow Query Log
- Performance/Load Testing Utility (mysqlslap)
- Improved! Full Text Search (faster, new dev templates)
- Improved! Archive engine (better compression, more features)
- Improved! User session and problem SQL identification
- Improved! MySQL embedded library (libmysqld)
- Additional INFORMATION_SCHEMA objects
- Faster data import operations (parallel file load)
- ACID Transactions to build reliable and secure business critical applications
- Stored Procedures to improve developer productivity
- Triggers to enforce complex business rules at the database level
- Views to ensure sensitive information is not compromised
- Information Schema to provide easy access to metadata
- Pluggable Storage Engine Architecture for maximum flexibility
- Archive Storage Engine for historical and audit data
# Functionality added or changed:
* Support for the IBMDB2I storage engine has been removed.
* The pstack library was nonfunctional and has been removed, along with the --with-pstack option for configure. The --enable-pstack option for mysqld is deprecated and will be removed in MySQL 5.5.
# Bugs fixed:
* Performance: InnoDB Storage Engine: Improved concurrency when several ANALYZE TABLE or SHOW TABLE STATUS statements are run simultaneously for InnoDB tables.
* InnoDB Storage Engine: For an InnoDB table created with ROW_FORMAT=COMPRESSED or ROW_FORMAT=DYNAMIC, a query using the READ UNCOMMITTED isolation level could cause the server to stop with an assertion error, if BLOB or other large columns that use off-page storage were being inserted at the same time.
* Partitioning: An INSERT ... ON DUPLICATE KEY UPDATE column = 0 statement on an AUTO_INCREMENT column caused the debug server to crash.
* Several compilation problems were fixed.
* Passing a string that was not null-terminated to UpdateXML() or ExtractValue() caused the server to fail with an assertion.
* Queries executed using the Index Merge access method and a temporary file could return incorrect results.
* The find_files() function used by SHOW statements performed redundant and unnecessary memory allocation.