From MySQL AB
One of the reasons MySQL is so popular is that it runs on so many platforms. Whether you run Windows, Mac OSX, Linux, OpenSolaris, or some other platform, there is likely a matching version of MySQL. Because each of these popular platforms is unique, so are the installation procedures for them. In this section, we provide links to tutorials that details how to install MySQL on your platform of choice.
MySQL is a multithreaded, multi-user, SQL Database Management System
* A broad subset of ANSI SQL 99, as well as extensions
* Cross-platform support
* Stored procedures
* updatable Views
* True VARCHAR support
* Strict mode
* X/Open XA distributed transaction processing (DTP) support; two phase commit as part of this, using Oracle's InnoDB engine
* Independent storage engines (MyISAM for read speed, InnoDB for transactions and referential integrity, Archive for storing historical data in little space)
* Transactions with the InnoDB, BDB and Cluster storage engines; savepoints with InnoDB
* SSL support
* Query caching
* Sub-SELECTs (i.e. nested SELECTs)
* Replication with one master per slave, many slaves per master, no automatic support for multiple masters per slave.
* Full-text indexing
New in MySQL 5.5.25:
Functionality Added or Changed:
- The --safe-mode server option now is deprecated and will be removed in MySQL 5.6.
- Performance: InnoDB: Improved the algorithm related to adaptive flushing. This fix increases the rate of flushing in cases where compression is used and the data set is larger than the buffer pool, leading to eviction.
- InnoDB: In a transaction using the REPEATABLE READ isolation level, an UPDATE or DELETE statement for an InnoDB table could sometimes overlook rows recently committed by other transactions. As explained in Section 22.214.171.124, “Consistent Nonlocking Reads”, DML statements within a REPEATABLE READ transaction apply to rows committed by other transactions, even if a query could not see those rows.
- InnoDB: The Innodb_buffer_pool_pages_flushed status variable was incorrectly set to twice the value it should be. Its value should never exceed the value of Innodb_pages_written.
- InnoDB: The error handling and message was improved for attempting to create a foreign key with a column referencing itself. The message suggested a potential problem with the data dictionary, when no such problem existed.
- InnoDB: The CHECK TABLE statement could fail for a large InnoDB table due to a timeout value of 2 hours. For typical storage devices, the issue could occur for tables that exceeded approximately 200 or 350 GB, depending on I/O speed. The fix relaxes the locking performed on the table being checked, which makes the timeout less likely. It also makes InnoDB recognize the syntax CHECK TABLE QUICK, which avoids the possibility of the timeout entirely.
- Replication: It was theoretically possible for concurrent execution of more than one instance of SHOW BINLOG EVENTS to crash the MySQL Server.
- Replication: Statements using AUTO_INCREMENT, LAST_INSERT_ID(), RAND(), or user variables could be applied in the wrong context on the slave when using statement-based replication and replication filtering server options
- Replication: An INSERT into a table that has a composite primary key that includes an AUTO_INCREMENT column that is not the first column of this composite key is not safe for statement-based binary logging or replication. Such statements are now marked as unsafe and fail with an error when using the STATEMENT binary logging format.
- SHOW TABLES was very slow unless the required information was already in the disk cache.