Saturday, December 09, 2006

mysql will now support scheduled events

By Justin Silverton

Mysql 5.1 beta has recently been released. It is only a beta (and should not be used in a production environment), but it does show us some of the new features that will appear in future, stable, releases:
  • Partitioning: This capability enables distributing portions of individual tables across a filesystem, according to rules which can be set when the table is created. In effect, different portions of a table are stored as separate tables in different locations, but from the user point of view, the partitioned table is still a single table. Syntactically, this implements a number of new extensions to the CREATE TABLE, ALTER TABLE, and EXPLAIN ... SELECT statements. As of MySQL 5.1.6, queries against partitioned tables can take advantage of partition pruning. In some cases, this can result in query execution that is an order of magnitude faster than the same query against a non-partitioned version of the same table.
  • Row-based replication: Replication capabilities in MySQL originally were based on propagation of SQL statements from master to slave. This is called statement-based replication. As of MySQL 5.1.5, another basis for replication is available. This is called row-based replication. Instead of sending SQL statements to the slave, the master writes events to its binary log that indicate how individual table rows are effected. As of MySQL 5.1.8, a third option is available: mixed. This will use statement-based replication by default, and only switch to row-based replication in particular cases.
  • Plugin API: MySQL 5.1 adds support for a very flexible plugin API that enables loading and unloading of various components at runtime, without restarting the server. Although the work on this is not finished yet, plugin full-text parsers are a first step in this direction. This allows users to implement their own input filter on the indexed text, enabling full-text search capability on arbitrary data such as PDF files or other document formats. A pre-parser full-text plugin performs the actual parsing and extraction of the text and hands it over to the built-in MySQL full-text search.
  • Event scheduler: MySQL Events are tasks that run according to a schedule. When you create an event, you are creating a named database object containing one or more SQL statements to be executed at one or more regular intervals, beginning and ending at a specific date and time. Conceptually, this is similar to the idea of the Unix crontab (also known as a “cron job”) or the Windows Task Scheduler.
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