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
# Bugs fixed:
* Partitioning: A problem with a previous fix for poor performance of INSERT ON DUPLICATE KEY UPDATE statements on tables having many partitions caused the handler function for reading a row from a specific index to fail to store the ID of the partition last used. This caused some statements to fail with Can't find record errors.
* An assertion was raised if an XA COMMIT was issued when an XA transaction had already encountered an error (such as a deadlock) that required the transaction to be rolled back.
* On some systems, debug builds of comp_err.c could fail due to an uninitialized variable.
* The server read one byte too many when trying to process an XML string lacking a closing quote (') or double quote (") character used as an argument for UpdateXML() or ExtractValue().
* Attempting to create a spatial index on a CHAR column longer than 31 bytes led to an assertion failure if the server was compiled with safemutex support.
* Aggregation followed by a subquery could produce an incorrect result.
* An incorrect character set pointer passed to my_strtoll10_mb2() caused an assertion to be raised.
* mysqldump did not quote database names in ALTER DATABASE statements in its output, which could cause an error at reload time for database names containing a dash.
* The MYSQL_HOME environment variable was being ignored.
* If a multiple-table update updated a row through two aliases and the first update physically moved the row, the second update failed to locate the row. This resulted in different errors depending on storage engine, although these errors did not accurately describe the problem:
- MyISAM: Got error 134 from storage engine
- InnoDB: Can't find record in 'tbl'
For MyISAM, which is nontransactional, the update executed first was performed but the second was not. In addition, for two equal multiple-table update statements, one could succeed and the other fail depending on whether the record actually moved, which is inconsistent.
Now such an update returns an error if it will update a table through multiple aliases, and perform an update that may physically more the row in at least one of these aliases.
* SHOW WARNINGS output following EXPLAIN EXTENDED could include unprintable characters.
* When CASE ... WHEN arguments had different character sets, 8-bit values could be referenced as utf16 or utf32 values, causing an assertion to be raised.
* Bitmap functions used in one thread could change bitmaps used by other threads, causing an assertion to be raised.