发布于 2016-04-19 06:51:09 | 60 次阅读 | 评论: 0 | 来源: 网友投递
MariaDB数据库
MariaDB基于事务的Maria存储引擎，替换了MySQL的MyISAM存储引擎，它使用了Percona的 XtraDB，InnoDB的变体，分支的开发者希望提供访问即将到来的MySQL 5.4 InnoDB性能。这个版本还包括了 PrimeBase XT (PBXT) 和 FederatedX存储引擎。
MariaDB 10.2.0 Alpha 发布了。
主要更新内容：
Syntax:
Window functions have been introduced. This release adds support for a limited set of functions, and the basic execution algorithm. Development continues to expand the set of supported functions and optimize the execution.
The SHOW CREATE USER statement was introduced.
New CREATE USER options for limiting resource usage and tls/ssl.
New ALTER USER statement.
Scripts:
Continuous binary log backup has been added to mysqlbinlog - MDEV-8713.
mysql_zap and mysqlbug have been removed - MDEV-7376, MDEV-8654.
Information Schema:
Added an information schema plugin to report all user variables, which creates the Information Schema USER_VARIABLES Table - MDEV-7331.
Variables:
aria_recover has been renamed to aria_recover_options - MDEV-8542.
The server version can now be faked to work around dated applications that require a particular version string - MDEV-7780
EXPLAIN:
EXPLAIN FORMAT=JSON now shows outer_ref_condition field which contains the condition that the(?) SELECT checks on each re-execution - MDEV-9652.
EXPLAN FORMAT=JSON now shows sort_key field which shows the sort criteria used by filesort operation. (commit 2078392)
EXPLAIN used to show incorrect information about how the optimizer resolved ORDER BY clause or Distinct. This is a long-standing problem coming from MySQL. Now, after MDEV-8646 and related fixes, the problem doesn't exist anymore. (For testcases, see MDEV-7982, MDEV-8857, MDEV-7885)
Optimizations:
Connection setup was made faster by moving creation of THD to new thread (MDEV-6150)
Code:
"fast mutexes" have been removed. These aren't faster than normal mutexes, and have been disabled by default for years - MDEV-8111.